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STUDIES ON % 

MESOZOIC AND CAINOZOIC 
DINOFLAGELLATE CYSTS 



R. J. DAVEY, C. DOWNIE, 
W. A. S. SARJEANT & G. L. WILLIAMS 



BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Supplement 3 

LONDON : 1966 



STUDIES ON MESOZOIC AND CAINOZOIC J 

DINQFLAGELLATE. CYSTS %>,„.. tt <S 




By 
ROGER JACK DAVEY 

(Dept. Geology, Nottingham University) 

CHARLES DOWNIE, Ph.D. 

(Dept. Geology, Sheffield University) 

WILLIAM ANTONY SWITHIN SARJEANT, Ph.D. 

(Dept. Geology, Nottingham University) 

and 
GRAHAM LEE WILLIAMS, Ph.D. 

(Dept. Geology, Sheffield University) 



26 Plates; 64 Text-figures 



BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Supplement 3 

LONDON : 1966 



THE BULLETIN OF THE BRITISH MUSEUM 

(natural history), instituted in 1949, is issued in 
five series corresponding to the Departments of the 
Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate Supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Supplement No. 3 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 



Trustees of the British Museum (Natural History) 1966 



TRUSTEES OF THE 
BRITISH MUSEUM (NATURAL HISTORY) 

Issued 20 December, 1966 Price £y 



STUDIES ON MESOZOIC AND CAINOZOIC 
DINOFLAGELLATE CYSTS 

By R. J. DAVEY, C. DOWNIE, 
W. A. S. SARJEANT & G. L. WILLIAMS 



CONTENTS 

I. Introduction . . . . • 

II. The morphology, terminology and classification of fossil 
dinoflagellate cysts (C. Downie & W. A. S. Sarjeant) 
Morphology and terminology 
Classification ..... 

III. Stratigraphy and historical background 

a. The Speeton Clay (W. A. S. Sarjeant) 

b. The Lower Chalk (R. J. Davey) 

c. The London Clay (G. L. Williams & C. Downie) 

IV. The genera HYSTRICHOSPHAERA and ACHOMOSPHAERA 

(R. J. Davey & G. L. Williams) . 

Introduction ..... 
Genus Hystrichosphaera O. Wetzel 
Hystrichosphaera ramosa (Ehrenberg) 
var. ramosa nov. . 
gracilis nov. . 
granosa nov. 
multibrevis nov. 
membranacea (Rossignol) 
granomembranacea nov. 
reticulata nov. 
cingulata (O. Wetzel) 
var. reticulata nov. 
crassimurata sp. n. 
crassipellis Deflandre & Cookson 
perforata sp. n. 
buccina sp. n. 
cornuta Gerlach 
var. laevimura nov. 
cf. cornuta Gerlach 
monilis sp. n. 
sp. . 
Genus Achomosphaera Evitt 

Achofnosphaera ramulifera (Deflandre) 
var. perforata nov. . 
alcicornu (Eisenack) 
sagena sp. n. . 
neptuni (Eisenack) . 
Other Species .... 

Conclusions ..... 
V. The genus HYSTRICHOSPHAERIDIUM and its allies (R. J 
Davey & G. L. Williams) 

Introduction ..... 
Genus Hystrichosphaeridium Deflandre 

Hystrichosphaeridium tubiferum (Ehrenberg) 
var. brevispinum nov. 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Page 



deanei sp. n. . 






58 


simplicispinum sp. n. 




59 


patulum sp. n. 




60 


arborispinum sp. n. 




61 


salpingophorum (Deflandre) 




61 


costatum sp. n. 




62 


readei sp. n. . 




64 


radiculatum sp. n. . 




65 


manlelli sp. n. 




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latirictum sp. n. 




66 


recurvatum (H. H. White) 




67 


sheppeyense sp. n. . 




68 


bowerbanki sp. n. 




69 


Other Species ...... 




70 


Genus Oligosphaeridium nov. .... 




70 


Oligosphaeridium complex (H. H. White) 




7i 


reticulatum sp. n. . 




74 


vasiformum (Neale & Sarjeant) 




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macrotubulum (Neale & Sarjeant) 




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pulcherrimum (Deflandre & Cooksoi 


i) 


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prolixispinosum sp. n. . 




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Other Species .... 






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Genus Perisseiasphaeridium nov. 






78 


Perisseiasphaeridium pannosum sp. n. 






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Other Species .... 






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Genus Litosphaeridium nov. 






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Litosphaeridium siphoniphorum (Cookson 


& Eisenack 


) 


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inversibuccinum sp. n. 






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Other Species .... 






82 


Genus Cordosphaeridium Eisenack 






83 


Cordosphaeridium inodes (Klumpp) . 






83 


gracilis (Eisenack) 






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fibrospinosnm sp. n. 






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cracenospinum sp. n. 






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exilimurum sp. n. 






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latispinosum sp. n. 






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divergens (Eisenack) 






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multispinosum sp. n. 






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fasciatum sp. n. 






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Other Species .... 






9i 


Genus Polysphaeridium nov. 






9i 


Polysphaeridium subtile sp. n. . 






92 


pastielsi sp. n. 






92 


pumilun sp. n. 






93 


laminaspinosum sp. n. 






94 


Other Species .... 






95 


Genus Diphyes Cookson 






95 


Diphyes colligerum (Deflandre & Cookson' 






96 


Other Species .... 






97 


Genus Duosphaeridium nov. 






97 


Genus Tanyosphaeridium nov. 






98 


Tanyosphaeridium variecalamum sp. n. 






98 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



regulare sp. n. 
Other Species 
Genus Homotryblium nov. 

Homotvyblium tenuispinosum sp. n 
pallidum sp. n. 
Genus Callaiosphaeridium nov. . 

Callaiosphaeridium asymmetricum (Deflandre & Courteville) 
Other Species hitherto placed in Hystrichosphaeridium 
Conclusions ....... 

VI. DINOFLAGELLATE CYSTS WITH GONYAULAX TYPE TABULATION 

(W. A. S. Sarjeant) .... 
Introduction ..... 

A. Genera with precingular archaeopyle 
Genus Gonyaulacysta Deflandre . 

Gonyaulacysta gongylos sp. n. . 
palla sp. n. 
axicerastes sp. n. 
helicoidea (Eisenack & Cookson) 
episoma sp. n. . 
hadra sp. n. 
orthoceras (Eisenack) 
aichmetes sp. n. 

cassidata (Eisenack & Cookson) 
whitei sp. n. 
fetchamensis sp. n. 
Other Species 
Genus Acanthogonyaulax nov. 
Genus Heslertonia nov. 

Heslertonia heslertonensis (Neale & Sarjeant) 
Genus Leptodinium Klement 

Leptodinium alectrolophum sp. n. 
Other Species .... 

Genus Raphidodinium Deflandre 
Genus Psaligonyaulux nov. 

Psaligonyaulax deflandrei sp. n. 
Other Species .... 

Genus Hystrichosphaeropsis Deflandre 
Genus Carpodinium Cookson & Eisenack 
Genus Rhynchodiniopsis Deflandre 
Genus Hystrichodinium Deflandre 
Hystrickodinium pulchrum Deflandre 
Other Species .... 

Genus Heliodinium Alberti 
Heliodinium voigti Alberti 

patriciae Neale & Sarjeant 

B. Genera with apical archaeopyle 
Genus Meiourogonyaulax nov. 

Meiourogonyaulax valensii sp. n. 

Other Species .... 

Genus Xiphophovidium nov. 

Xiphophoridium alatum (Cookson & Eisenack) 
Genus Belodinium Cookson & Eisenack 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Genus Microdinium Cookson & Eisenack 

Microdinium cf. ornatum Cookson & Eisenack 
setosum sp. n. . 
Genus Glyphanodinium Drugg .... 
Genus Eisenackia Deflandre & Cookson 

C. Genera with epitractal archaeopyle . 
Genus Rhaetogonyaulax nov. .... 
Genus Dichadogonyaulax nov. .... 

D. Genera with cingular archaeopyle . 
Genus Ctenidodinium Deflandre 
Genus Wanaea Cookson & Eisenack . 

E. Genera with archaeopyles formed by other means 
Genus Pluriarvalium Sarjeant .... 

Pluriarvalium osmingtonense Sarjeant 
Conclusions ....... 

VII. Fossil dinoflagellate cysts attributed to BALTISPHAER- 
IDIUM (R. J. Davey, C. Downie, W. A. S. Sarjeant & G. L. 
Williams) ....... 

Introduction ...... 

The Species hirsulum (Ehrenberg) and striolatum (Deflandre) 
Genus Surculosphaeridium nov. . 

Surculosphaeridium cribrotubiferum (Sarjeant) 
vestitum (Deflandre) . 
longifurcatum (Firtion) 
Genqs Exochosphaeridium nov. . 
Exochosphaeridium phragmites sp. n. 
Other Species ..... 

Genus Cleistosphaeridium nov. . 

Cleistosphaeridium diversispinosum sp. n. 

ancoriferum (Cookson & Eisenack) 
heteracanthum (Deflandre & Cookson) 
flexuosum sp. n. . 
disjunctum sp. n. 
Other Species ....... 

Genus Prolixosphaeridium nov. ..... 

Prolixosphaeridium deirense sp. n. . 

granulosum (Deflandre) 
Other Species ....... 

Other Mesozoic and Cainozoic Species attributed to Balti- 
sphaeridium ...... 

VIII. The genus HYSTRICHOKOLPOMA (G. L. Williams & C. 
Downie) ........ 

Introduction ....... 

Genus Hystrichokolpoma Klumpp 
Hyslrichokolpoma eisenacki sp. n. . 
var. turgidum nov. 
unispinum sp. n. . 
rigaudae Deflandre & Cookson 
Other Species ...... 

IX. WETZELIELLA from the London clay (G. L. Williams & C. 
Downie) ....... 

Introduction ...... 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Genus Wetzeliella Eisenack 

Subgenus Wetzeliella (Wetzeliella) Eisenack 
Wetzeliella (Wetzeliella) articulata Eisenack 
var. conopia nov. 
clathrata Eisenack 
coleothrypta sp. n. 
reticulata sp. n. 
tenuivirgula sp. n. 
var. crassoramosa nov 
homomorpha Deflandre & Cookson 
var. quinquelata nov 
ovalis Eisenack 
condylos sp. n. 
similis Eisenack 
solida (Gocht) 
symmetrica Weiler 
var. lobisca nov. 
varielongituda sp. n. 
Subgenus Wetzeliella (Rhombodinium) Gocht 
Wetzeliella (Rhombodinium) glabra Cookson 
X. Further dinoflagellate cysts from the Speeton 
(lower cretaceous) (W. A. S. Sarjeant) 
Introduction ..... 
Genus Netrelytron Sarjeant 
Nett elytron trinetron sp. n. 
Other Species .... 

Genus Par anetr elytron nov. 

Paranetrelytron strongylum sp. n. 
Genus Muderongia Cookson & Eisenack 

Muderongia staurota sp. n. 
Genus Apteodinium Eisenack 

Apteodinium maculatum Eisenack & Cookson 
Genus Doidyx nov. 

Doidyx anaphrissa sp. n. 
Genus Broomea Cookson & Eisenack . 

Broomea longicornuta Alberti 
Genus Odontochitina Deflandre . 

Odontochitina operculata (O. Wetzel) 
Genus Fromea Cookson & Eisenack 

Fromea amphora Cookson & Eisenack 
Genus Systematophora Klement 

Systematophora schindewolfi (Alberti) 
Genus Gardodinium Alberti 

Gardodinium eisenacki Alberti 
Genus Dingodinium Cookson & Eisenack 

Dingodinium albertii sp. n. 
Genus Pareodinia Deflandre 

Pareodinia ceratophora Deflandre 
Genus Sirmiodinium Alberti 

Sirmiodinium grossi Alberti 
Genus Cometodinium Deflandre & Courteville 
Cometodinium sp. .... 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Genus Wetzeliella Eisenack 

Wetzeliella neocomica Gocht 
Conclusions ...... 

XI. Further dinoflagellate cysts from the London clay (G. L 
Williams & C. Dovvnie) .... 

Introduction ...... 

Genus Adnatosphaeridium nov. . 
Adnatosphaeridium viltatiim sp. n. 

multispinosum sp. n. 
patulum sp. n. . 
Other Species ..... 

Genus Membranilarnacia Eisenack 

Membranilarnacia reticulata sp. n. 
Genus Nematosphaeropsis Deflandre & Cookson 

Nematosphaeropsis balcombiana Deflandre & Cookson 
Genus Cannosphaeropsis O. Wetzel 

Cannosphaeropsis reticulensis Pastiels 
Genus Cyclonephelium Deflandre & Cookson 
Cyclonephelium divaricatum sp. n. 

exuberans Deflandre & Cookson 
ordinatum sp. n. 
pastielsi Deflandre & Cookson 
Genus Areoligera Lejeune-Carpentier . 
Areoligera coronata (O. Wetzel) 

cf. coronata (O. Wetzel) . 
cf. medusettiformis (O. Wetzel) 
cf. senonensis Lejeune-Carpentier 
Genus Deflandrea Eisenack 

Deflandrea phosphoritica subsp. phosphoritica Cookson & 
Eisenack ...... 

subsp. australis Cookson & Eisenack 
denticulata Alberti. 
oebisfeldensis Alberti 
wardenensis sp. n. . 
Genus Thalassiphora Eisenack & Gocht 
Thalassiphora pelagica (Eisenack) 
delicata sp. n. . 
XII. Acknowledgments ..... 

XIII. References ...... 

XIV. Index 



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SYNOPSIS 

The morphology of fossil dinoflagellate cysts is discussed ; the cysts are shown to fall into 
three broad groups (" proximate ", " chorate " and " cavate "), which are interpreted as 
indicating different modes of formation. New terms are proposed, to enable more precise 
description of cyst morphology. The principal genera are reconsidered, in the light of new 
information from studies of assemblages from the Cretaceous (Speeton Clay and Chalk) and 
Eocene (London Clay) of England. 27 new genera are proposed and emendations are given to 
the diagnoses of 16 existing genera ; 64 new species are described and the diagnoses of nine 
existing species are emended. In addition, the generic allocation of other species already 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 9 

described, from all stratigraphic levels in the Mesozoic and Cainozoic, is reviewed and generic 
transfers are proposed where necessary. The resultant picture of the stratigraphic distribution 
of genera and species emphasizes the value of these microfossils as stratigraphic indices. 



I. INTRODUCTION 

During the last few years, research into the nature and distribution of fossil dino- 
flagellate cysts has been very active, stimulated by realization of the potential value 
of these microfossils in the correlation of marine strata and by their biological 
interest. The great bulk of recent researches has been made by French and German 
palynologists, notably Deflandre, Valensi, Eisenack and Gocht. 

In Britain, a brief period of interest followed Ehrenberg's initial discovery of these 
fossils in flints and his visit to England in 1838: however, after 1850, no further 
attention was paid to these fossils for a century. In 1957 Downie described a number 
of types from the Upper Kimmeridge Clay (Kimmeridgian) : this was the first study 
of British Jurassic dinoflagellates. Subsequently Sarjeant, in a series of publications, 
has described assemblages from the Cornbrash, Oxford Clay, Corallian and Ampthill 
Clay (Callovian to Oxfordian) : species described by this author (1962) from the 
Cotham Beds (Rhaetic) include the earliest known clearly tabulate cysts. The 
distribution of dinoflagellate cysts in the Lias has been studied by Wall (1965). 

The first British Lower Cretaceous assemblage to be described was from the 
Hauterivian section of the Speeton Clay (Neale & Sarjeant 1962), species from other 
levels of the Speeton Clay are described herein. An assemblage from the Cambridge 
Greensand (Middle Cretaceous) has been described by Cookson & Hughes (1964). 
Since 1850, no further work has been published on the Upper Cretaceous : the first 
results of studies by Davey, at present in progress, are included in the present work. 

No British Tertiary assemblages have yet been described. Dinoflagellate cysts 
from the London Clay (Eocene) have been mentioned by Eagar & Sarjeant (1963) 
and figured by Macko (1963), but the first extended study was that made by G. L. 
Williams (thesis, 1964), of which results are given herein. 

No Quaternary assemblages have been described ; work by Deflandre referred to 
by West (1961) has not been published. 

There has been considerable progress in recent years in our understanding of the 
nature of these cysts, largely as a result of the studies of Evitt (1961, 1963, Evitt & 
Davidson 1964). He has elucidated some of their fundamental structures and drawn 
attention to the importance of the cyst openings (archaeopyles) and of structures 
representing a reflected tabulation, thus effectively demonstrating the affinity of 
many formerly problematic genera (the " hystrichospheres " sensu stricto). 

This paper comprises a full-scale review of certain of the principal genera of fossil 
dinoflagellate cysts, involving extensive revision of generic diagnoses and the 
erection of new taxa. In addition, new genera and species are described from 
various Mesozoic and Tertiary horizons. 



io MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

II. THE MORPHOLOGY, TERMINOLOGY AND CLASSIFICATION OF 
FOSSIL DINOFLAGELLATE CYSTS 

By C. DOWNIE & W. A. S. SARJEANT 

In the description of fossil dinoflagellates in the past, the terms used have been 
largely borrowed from modern plankton descriptions. This is appropriate enough : 
however, as studies of fossil dinoflagellates have developed, structures have been 
discovered for which no terms exist and the use of descriptive terms, without 
specification of precise meanings, has produced, on the one hand, ambiguity, on the 
other hand, the failure to distinguish between different, albeit broadly similar, 
structures — cf., for example, past usage of the terms " spine " and " tube " in 
description of appendages. 

The work of Evitt (1961, 1965, in press) has gone some way towards the establish- 
ment of precise terms for some morphological characters. In the present work, a 
number of new terms are proposed which, it is hoped, will form a workable basis for 
future descriptions. 

In addition, the existence of broad groupings of morphologically similar dino- 
flagellate cysts has become apparent : these groupings appear to have considerable 
stratigraphic meaning. The classification at present in use is criticized for not 
taking cyst structure into account. 

Morphology and terminology, (i) Cysts and Motile Stage Thecae. 

Evitt & Davidson (1964) have described the process of cyst formation in some 
Recent dinoflagellates and have shown that these resting cysts are of types closely 
resembling some of the most common fossil species. They conclude that most, if not 
all, of the fossil remains of dinoflagellates are cysts. These cysts are smaller than 
the motile stage cell and are formed by the deposition of an ellipsoidal or spherical 
wall some distance inside the motile stage envelope (or theca if hardened) . This wall 
in fossil and Recent cysts is often seen to be constructed of two layers, which we 
propose to call the endophragm and the periphragm. The outer layer, or peri- 
phragm, usually carries extensions, either in the form of spines or as lists, which 
extend out to the position of the formal thecal wall and appear to have acted as 
supports during the period of cyst formation (Text-fig. 1). 

Many kinds of fossil dinoflagellate cysts are equipped with a special opening which 
functions when the cyst contents are to be released. These openings, called archaeo- 
pyles by Evitt, generally have a definite polygonal shape and are fixed in location in 
any particular species. Their presence in a fossil demonstrates that it is a cyst. 
Fossil remains of potentially motile dinoflagellates lack an archaeopyle and have a 
cingulum, or transverse furrow, in the form of a continuous spiral groove which has no 
impediments such as spines and septae crossing its track, indicating that this was the 
former position of the transverse flagellum (Text-fig. 2). 

Tabulation, which is a striking feature of the living armoured dinoflagellates, can 
also be represented in cysts, often highly modified, but its presence or absence is not 
determinative in distinguishing cysts from motile stage thecae. 



MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 




B 




Fig. i. Oligosphaeridium vasiformum (Neale & Sarjeant), a typical chorate cyst, showing 
the presumed method of cyst formation, a. The probable original tabulation of the 
dinoflagellate, which corresponds to that of Gonyaulacysta. (The apical tabulation is 
wholly speculative.) b, The cyst forming within the dinoflagellate theca, attached to the 
cell membrane by its processes, c, The abandoned cyst as found, with an apical archaeo- 
pyle. [After Sarjeant (1965) reproduced by permission of the Editor of " Endeavour ".] 



12 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



The term " ambitus " applied to dinoflagellates refers to the test outline viewed 
from the dorsal or ventral side. 

(2) The Morphology of Motile Stage Thecae. 

Modern dinoflagellates may be thin-walled or may have robust cellulosic tests 
(thecae), which are clearly divided into fields by sutures in the tabulate genera. 
Text-fig. 2A shows a test of this type and indicates the terminology used to describe 
it. Other morphological structures are shown in Text-figs. 3, 4. 

(3) Fossilized Motile Thecae. 

Very few fossil dinoflagellates could be considered as the remains of motile stage 
thecae. The strongest claims can be made for some species of Peridinium and 
Gymnodinhim from the Upper Cretaceous which lack archaeopyles and show no other 
structures characteristic of cysts. 




Fig. 2. The tabulation of a modern dinoflagellate, compared with that of a proximate 
dinoflagellate cyst, a, Gonyaulax polyedra, a dinoflagellate of present day warm and 
temperate seas. After Kofoid. b, Gonyanlacysta jurassica, from the Upper Jurassic ; 
a proximate cyst with a precingular archaeopyle. [After Sarjeant (1965) reproduced by 
permission of the Editor of " Endeavour ".] 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



13 



(4) The Morphology of Cysts. 

(a) Major Cyst Types. 

The cysts are always smaller than the motile cell and can be grouped according to 
their degree of contraction. The degree of contraction also affects their general 
appearance, for those which are most condensed bear little superficial resemblance 
to the parent cell, whereas those that are near the motile cyst in size closely resemble 
it in appearance. Consequently two groups of cysts are here recognized, the chorate 
(or condensed) cysts and the proximate cysts. 

In both these groups of cysts, the two wall layers are generally in close contact and 
only rarely come apart, but there is a third group, here called the cavate cysts, in 
which a space, or spaces of notable size, occurs between the periphragm and endo- 
phragm. This space is here named the pericoel ; it separates an inner body (cap- 
sule) formed by the endophragm from the outer cyst wall, the cavity of this inner 
body is called the endocoel. 

(b) Cyst Openings. 

The polygonal openings found on cysts have been called pylomes by Eisenack. 
This is, however, a broad term and includes also circular or slit-like openings which 
are in no way characteristic of, or confined to, the dinoflagellates. Evitt's term 
archaeopyle refers specifically to those kinds of pylome which characterize some 
dinoflagellate cysts. They are usually polygonal and precisely located and orientated 
on the test, corresponding to specific locations in the structure of the tabulate dino- 
flagellates. The terminology used here generally corresponds to that proposed by 
Evitt (1961, text-figs. 5-8), with the addition of epitractal, for archaeopyles formed 
by breakage parallel, and immediately anterior to, the cingulum (equivalent to 
epithecal archaeopyles of Norris 1965), and cingular, for archaeopyles formed by 



A A 




11 



Y7 



conical subconical tapering cylindrical infundibular flared tubiform buccinate 



lagenate bulbose 



annular 

complex 



soleate 
c mplex 



J> 



r f 



arcuate 
complex 



LjUJWl-iHv 
•I }■ 



■ifMnit' 



linear simulate 

complex complex 



o 



CD' 



erect curved sinuous 



latispinous 



cross sections 



slender 



□ 



Fig. 3. Illustrations of the terms used to describe the overall shape of the 
processes and process complexes. The distal end is uppermost in each case. 



M 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 



breakage along and within the cingulum. Apical archaeopyles are called haplo- 
tabular when they consist of a single plate and tetratabular when they have four. 

(5) Proximate Cysts. 

The proximate cysts are an important group, which have always been recognized 
as dinoflagellates because their resemblance to modern forms is very close. Never- 
theless, although all the features of tabulation may easily be determined on good 
specimens, they are not motile thecae, but cysts. The terms epitheca and hypo- 
theca used for motile stages, are therefore inappropriate. It is here proposed that 
their cyst equivalents should be termed epitract and hypotract, names suggested by 
G. L. Williams (thesis, 1964). 

Contraction in the formation of the proximate cyst is generally to about \ or § of 
the original volume; this can roughly be gauged by the height of the periphragm 

Radius of endocoel 



spines or lists. The ratio 



= 0-8 constitutes a rough limit to the 



Radius overall 
proximate cysts. 

The periphragm often forms extensions which bear a close relationship to the 
presumed tabulation of the motile stage theca. These extensions are nearly always 
sutural (i.e. reflecting the site of the sutures on the motile stage) and most often 
consist of continuous crests or lists, often with serrate or denticulate edges. Less 
commonly, lines of small solid spines or tubercles mark the reflected sutures. 

Subdivision of the proximate group of cysts is based on a number of features among 
which the reflected tabulation, the overall shape of the test (i.e. elongation, number of 
horns) and the nature of the archaeopyle are important. 

Typical of the proximate cysts is the genus Gonyaulacysta. The group as a whole 
is more characteristic of Upper Jurassic-Lower Cretaceous than of later strata. 





c aulit lorate 



bulbous 
jvexate capitate 



foliate 



bifid 



I r T n n 



oblate branched trifurcate 

digitate bifurcate entire 



fenestrate 



|****T h(wJ 



aculeate denticulate patulate orthogonal 

secate recurved dirigate 



^f= 



Fig. 4. Illustrations of the terms used to describe the various kinds of 
distal termination of the processes. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 15 

(6) Chorate Cysts. 

Chorate cysts in general resemble Hystrichosphaeridium and include all the 

typical hystrichospheres. They are distinguished from proximate cysts by the 

greater contraction that took place during cyst formation, for the cyst has only 

. Radius of endocoel 

about I the volume of the motile cell and the contraction ratio „ ,. n 

Radius overall 

is typically about 0-6. As a consequence of this greater contraction the tabulation 
is often only indirectly determinable, if at all, and the general appearance is not 
dinoflagellate-like. Furthermore, the outgrowths of the periphragm are longer and 
often exceed in length the endocoel radius. These outgrowths are commonly spine- 
like, and are either located from the site of the sutures (sutural appendages) or 
within the edges of the plates (intratabular appendages). 

Intratabular appendages occur in various ways, but are usually either hollow or 
grouped in patterns related to the tabulation. The hollow processes are open at the 
distal end in Hystrichosphaeridium, but in Cleistophaeridutm they are closed distally. 
So far, no species definitely identified as a dinoflagellate cyst has spines which open 
into the endocoel. 

The open-ended processes have various kinds of distal openings, which may flare 
like trumpets or constrict ; various kinds are illustrated in Text-figs. 3, 4. In 
some cyst groups the processes may be connected distally by narrow solid rods 
(trabeculae) : in others a thin membrane (ectophragm) may still persist between the 
distal ends. The ectophragm must have been laid down very close to the motile cell 
envelope. Often only one appendage occurs on each plate, but there may be more, 
and when the appendages are very numerous the tabulation may not be determinable 
at all. 

Other kinds of intratabular appendages are often found to be solid and to occur in 
groups (see Text-figs. 3, 4). Polystephanephorus is characterized by annulate 
groups, and Areoligera by coronate and soleate groups. Usually no more than one 
group is found associated with one plate so that they are useful in determining the 
tabulation. 

Sutural elements may consist of rows of spines or of spines situated only at plate 
corners (gonal spines), but commonly these spines have merging bases forming 
continuous flanges or lists as in the proximate cysts. These elements are usually 
solid but small pyramidal cavities may develop at the base of the gonal spines, 
which in Hystrichosphaeropsis begin to run together to form a larger, more 
continuous cavity. 

Several sub-divisions of the chorate group of cysts are found to be useful. The 
typical chorate cysts are represented by highly condensed forms like Hystrichosphae- 
ridium and Cleistosphaeridium with cylindrical or spine-like processes. Their 
condensation ratio is about o- 5 or o- 6 and the outgrowths are intratabular. Proximo- 
chorate cysts include forms like Hystrichosphaera which have generally lower conden- 
sation ratios (o-6-o-8) and sutural outgrowths which more readily indicate the 
tabulation. Raphidodinium is a highly condensed representative. The trabeculate 



16 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

chorate cysts are represented by Cannosphaeropsis ; and M embranilamacia is typical 
of the membranate group. 

A pterate group can also be recognized with Wanea as a representative, its main 
characteristic being its pronounced equatorial outgrowth in the form of solid processes 
linked distally or in mesh-like fashion. The marginate cysts form a group, typified 
by Areoligera, consisting of chorate cysts whose outgrowths are characteristically 
localized on the lateral margins, leaving the dorsal and more often the ventral 
surfaces free of large outgrowths. 

Chorate cysts have a very long history, but they are more important in the Upper 
Cretaceous and Tertiary than at any other time. 

(7) Cavate Cysts. 

In some forms already mentioned, small pericoels have been found between the 
endophragm and periphragm. In the cavate group of cysts, the pericoel is a domi- 
nant feature, so that the body consists of an inner body (capsule) formed by the 
endophragm and an enclosing body, formed by the periphragm, often of quite a 
different shape. 

The inner body is usually ellipsoidal, thick walled, with a smooth or granular 
surface. It may have an archaeopyle but rarely shows any sign of tabulation. In 
a few forms spinous projections bridge the gap between the endophragm and the 
periphragm, but in many the cavity is more or less continuous and contact between 
the two is either not apparent or occurs only at the mid-ventral line. The peri- 
phragm is usually thinner and often smooth. It does however quite often have an 
archaeopyle and may show a tabulation marked by sutural lines, or by intratabular 
spine pallisades as in Wetzeliella. The overall shape is an important feature in these 
cysts, especially the number and positions of the horns on the periphragm. 

A number of sub-groups are recognized depending on the degree of continuity of 
the pericoel. In typical cavate cysts like Deflandrea phosphoritica there is only one 
large pericoel extending over nearly all the body. In bicavate cysts there is a wide 
zone of contact round the equator which divides the pericoel into an apical and 
antapical part ; Triblastula is typical of this group. Stephodinmm represents a 
small group (the pterocavate cysts) with a pronounced equatorial pericoel. Small 
pericoels may occur in other groups such as the apical pericoels in some proximate 
cysts, the gonal pericoels in some Hystrichosphaera species. 

(8) Other Cyst Groups. 

In addition to the three main groups discussed so far one must recognize the 
existence of groups of fossil dinoflagellates with calcareous tests and with siliceous 
tests. Neither of these groups is being considered in this paper, although most 
appear to be non-motile and probably encysted. 

Classification. Eisenack (1964) published a classification of fossil dinoflagel- 
lates which is by far the most comprehensive classification yet attempted. In this 
paper he adopts a botanical system, which is welcomed. However, his classification 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 17 

cannot be considered satisfactory, because he does not allow enough importance to 
the fact that we are dealing with cysts. 

Evitt & Davidson (1964), Deflandre (1962) and Norris (1965) have cogently stated 
the taxonomic problem that arises because so little is known about the encystment of 
living species of dinoflagellates. Currently the classification of living species and 
genera is based on the tabulation and appearance of the motile stage cell, but it is 
now known (Evitt & Davidson 1964) that similar motile stages can produce grossly 
different cysts and an extensive reclassification is likely to ensue when more work has 
been done on encystment. It is therefore unsatisfactory to press fossil cysts into a 
taxonomic system based largely on living motile stages as Eisenack has done, when 
we know so little about the life cycles and important reclassification of the living 
forms is impending. 

The frequent dissimilarity between the motile and cyst stages means that attribu- 
tion of a cyst to a species based on a motile stage can only be confidently asserted on 
the direct evidence of cultures or on the circumstantial evidence of close geographic 
association of certain cyst types with certain motile stage types. Neither of these 
possibilities is available to the palynologist who at the most can hope to identify a 
fossil cyst with a Recent one by morphological comparison. In an overwhelming 
number of instances he can expect to find no exact counterpart, and his classification 
must be a classification of cysts. 

It is hoped to deal more thoroughly with the classification of fossil dinoflagellate 
cysts in a separate publication where the whole range of cyst types can be considered 
adequately. 



lS 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 
III. STRATIGRAPHY AND HISTORICAL BACKGROUND 



a. The Speeton Clay 

By W. A. S. SARJEANT 

The Speeton Clay is the lowest of the three horizons principally dealt with in 
this work. Two boreholes were put down through the Speeton Clay during the 
summer of i960 by Koninklijke Shell Exploratie en Produktie Laboratorium, 
Rijswijk, The Netherlands. The first of these, Shell Speeton No. 1, was sited near 
Speeton Beck (grid ref. TA.151753) and reached a depth of 135-25 metres (443 ft. 
11 in.) ; the second, Shell West Heslerton No. 1, was put down at West Heslerton, 
some 1-4 miles west of Speeton, reaching a depth of 117 metres (383 ft. 4 in.) without 
bottoming the Lower Cretaceous. Through the courtesy of Shell Internationale 
Research Maatschappij N.V., The Hague, Netherlands, specimens were made 
available for micropalaeontological and palynological study to various specialists. 
Results of study of the Speeton Clay ostracod faunas have been published by Neale 
(1960a, 1962a), Neale & Kilenyi (1961) and Kaye (1963a, 19636, 1964a). These 
authors also published accounts of the outcrop stratigraphy (Neale 19606, 19626 ; 
Kaye 19646) ; their accounts of the stratigraphy and ostracod faunas of the bore- 
holes are currently in press. 

The assemblages of fossil microplankton proved unexpectedly rich. They are 
dominated by dinoflagellate cysts, acritarchs being relatively infrequent. Studies 
have to date been concentrated on the assemblages from the West Heslerton bore- 
hole, a brief account of some new species from a Hauterivian horizon having already 
been published (Neale & Sarjeant 1962). The holotypes of the species described in 
that paper, formerly in the collections of the Sedimentology Research Laboratory, 
University of Reading, are now lodged in the British Museum (Natural History) 
under the following numbers : 



Species 


Reading Nos. 


B.M.(N.H.) 


Heslertonia heslertonensis 






(formerly Gonyaulax) 


44Y/8/10 


V.51713W 


Gonyaulacysta cretacea 






(formerly Gonyaulax) 


44Y/4/21 


V.5i 7 n(2) 


Cribroperidinium sepimentum 


44Y/7/7 


V.51712 (1) 


Gardodinium albertii 


44Y/1/28 


¥.51709(2) 


Pseudoceratium (Eopseudoceratium) gochti 


44Y/I/36 


V.51709 (4) 


Muderongia cruris 


44Y/4/1 


¥.51711(1) 


Heliodinium patriciae 


44Y/3/3 


V. 5 i 7 io(i) 


Oligosphaeridium vasiformum 






(formerly Hystrichosphaeridium) 






Holotype 


44Y/I/34 


V.5i7°9(3) 


Paratype 


44Y/1/26 


V.5i7°9(i) 


Oligosphaeridium macrotubulum 






(formerly Hystrichosphaeridium) 


44Y/7/20 


V.5I 7 I2(2) 


Systematophora complicata 


44Y/4/22 


V.5*7 ll (3) 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



19 



Subsequently, examination of asssemblages has been extended upwards into the 
Barremian. In the chapters which follow, the results are given of studies by R. J. 
Davey and the writer on the dinoflagellate cysts from five assemblages in the West 
Heslerton No. 1 Borehole, as follows : 



Depth 


Character of Sediment 


Stage 


19 


25/50 metres 


Soft, medium dark grey (N4) to 


Upper Barremian 






live grey (SY4/1) clay, containing 


(Middle part) 






much pyrite. 




39 


00/25 metres 


Softish, medium (N5) to olive 


Middle Barremian 






grey (5Y5/1) clay, pyritic, with 


(Cement Beds) 






some shell fragments. 




42 


■50/75 metres 


Lithology as last. 


Lower Barremian (top) 


99 


•25/50 metres 


Hard, medium olive grey (5Y5/1) 
siltstone, laminated and pyritic. 


Middle Hauterivian 


103 


•25/50 metres 


Well-laminated olive g re y 
(5Y6/1) pyritic clay, rather 
streaky, with shell fragments. 


Middle Hauterivian 



(The numbers in parentheses are the American Rock Colour Chart numbers.) 
For further stratigraphical information, see forthcoming paper by Neale & Kaye. 



b. The Lower Chalk 

By R. J. DAVEY 

Fossil microplankton from the Upper Chalk (Senonian) of Great Britain were first 
described in the mid-nineteenth century by a group of amateur microscopists, 
namely Mantell, Reade, Deane, White, Bowerbank and Wilkinson. After these 
initial studies no subsequent work was performed in Great Britain on Upper Creta- 
ceous microplankton until 1964, when Cookson & Hughes published a paper on 
microplankton from the Cambridge Greensand, of presumed basal Cenomanian age. 
The work referred to in the following chapters, on microplankton assemblages from 
the English Lower Chalk (Cenomanian) , is part of a larger study of the Cenomanian 
assemblages throughout the world. 

Specimens quoted in this paper as being of Cenomanian age have all been obtained 
from samples from H.M. Geological Survey Borehole at Fetcham Mill, Leatherhead, 
Surrey (National Grid Reference, TQ. 158565). At this locality the Cenomanian is 
197 feet thick and lies conformably on the Upper Greensand. The basal Ceno- 
manian is a grey, glauconitic impure chalk containing a relatively high percentage of 
clay minerals. The percentage of clay minerals progressively decreases towards the 
top of the stage where the Cenomanian is a hard, almost pure, white chalk. A full 
account of the stratigraphy appears in the Geological Survey Bulletin No. 23. 



20 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Ten samples, at twenty foot intervals, were analysed for their organic-shelled 
microplankton content. The microplankton content was quite rich and fairly well 
preserved. Cysts of dinoflagellates were predominant over acritarch remains, and 
spores and pollen were relatively rare. 



c. The London Clay 

By G. L. WILLIAMS & C. DOWNIE 

Dinoflagellate cysts (hystrichospheres) were first briefly recorded from the London 
Clay by E. W. Wetherell (1892). No further work was done on them for over 60 
years. They first came to the attention of one of us (CD.) in 1958, when Murray 
Hughes of the Geological Survey sent for identification a number of species picked 
out from washed foraminifera preparations which had come from London Clay at 
Isleworth, Middlesex. Mr. D. Curry (1958 : 56) had however previously exhibited 
hystrichospheres from the Eocene at a meeting of the Geologists' Association in 
November 1957. Subsequently Eager & Sarjeant (1963) recorded Hystricho- 
sphaeridium similarly obtained from Berkshire. Macko (1963) figured a variety of 
forms from the London Clay without identifying any of them conclusively. 

The first systematic work on the dinoflagellates of the formation was begun in i960 
in Sheffield by G. L. Williams. His thesis (1963) dealt with all the planktonic 
dinoflagellates and acritarchs in the samples examined. Many of these were 
derived from older formations and are being described elsewhere ; the indigenous 
acritarchs and dinoflagellates will be listed here, but the acritarchs will not be 
described. Dinoflagellates belonging to Hystrichosphaera, Haplosphaeridium, Clei- 
stosphaeridium, Hystrichosphaeridium and allied genera are treated by Davey & 
Williams in Sections IV and V of the present work. 

Stratigraphy. The London Clay is confined to two areas in Southern England, 
the London and Hampshire Basins respectively. They formed one continuous 
basin of deposition during Eocene times but subsequent orogenic movements 
and erosion have given rise to the intervening Wealden Dome separating the two 
main outcrops of the London Clay. The term basin when speaking of the two areas 
is therefore used in a structural sense referring to the present day conditions only. 
There is close similarity between the lithology of the London Clay of the western 
margin of the London Basin and of the Hampshire Basin where the " typical " stiff 
blue grey clay is increasingly replaced by arenaceous beds, loamy and sandy bands 
being common. 

To the east of the London Basin, the blue clay reaches its greatest thickness, at 
Sheppey, where it is estimated to be over 500 feet thick with little change in lithology 
throughout. Collecting was undertaken at three places, Studland Bay in Dorset, 
Whitecliff Bay in the Isle of Wight, both in the Hampshire Basin, and Sheppey in the 
London Basin. In addition, Professor H. L. Hawkins kindly provided samples from 
borehole cores from the Enborne Valley, lying in the west of the London Basin 
where the lithology shows striking similarities to that of the Hampshire Basin. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



SLUMPING' 



LENSES OF SANO 
IN CLAY 



I' 



LAND SLIP 



r 60" 



-30" 



L-0 
VERTICAL 
SCALE 



*WC 30 

"WC 29 

"WC 28 

WC 27 

"WC 26 

WC 25 

"WC 24 

WC 23 

WC 22 

WC 21 

* WC 20 

WC 19 

"WC 18 



*WC 17 

*WC 16 

WC 15 

* WC 14 

WC 13 

"WC 12 

WC II 

"WC 10 

WC 9 

*WC 8 

WC 7 

"WC 6 

WC 5 

*WC 4 

"WC 3 
"WC 2 
»WC I 



8A6SHOT 
SANDS 



• DENOTES SAMPLES THAT 
HAVE BEEN MACERATED 



T 

u 
p 

p 

E 
R 



.J'. 



READING 
BEDS 



TOP OF LONDON CLAY ACCORDING TO OSBORN WHITE 
YELLOW SAND 

YELLOW SAND 

TOP OF LONDON CLAY FROM FOSSIL AND LITHOLOGIC EVIDENCE 

ARGILLACEOUS SAND 

GREY BROWN SAND 

SANDY CLAY I' BAND OF IRONSTONE 

BLUE GREY CLAY, BANDS OF CEMENT STONE 

GREY BANDED SAND WITH PYRITES 

PEBBLE BED 

GREY ARENACEOUS CLAY 

241' 

ARENACEOUS GREY CLAY, CHANGE IN LITHOLOGY 

YELLOW SAND BECOMING COARSER MORE SANDY 

BLUE CLAY WITH SANDY BANDS, PYRITES 

BANDS OF LOAMY SAND COMMON IN CLAY, PYRITES 

ARENACEOUS FOSSILIFEROUS CLAY, CEMENT STONES 

BLUE GREY CLAY 



BLUE GREY CLAY WEATHERING BROWN 

CLAY WITH FLINTS AND CEMENT STONES 

TYPICAL BLUE GREY LONDON CLAY 

122' 

PYRITES 

DARK GREY ARENACEOUS CLAY WITH FLINT PEBBLES 

CARBONACEOUS YELLOW SAND 10' 

DARK GREY SANDY CLAY 

DARK GREY SANDY CLAY 

SANDY GLAUCONITIC DARK GREY CLAY 
WEATHERS TO LIGHTER COLOR 



LAMINATED GREY CLAY WITH PYRITES, 
►LIGNITE AND CEMENT STONES 



GREEN GLAUCONITIC ARGILLACEOUS SAND, FEW NODULES 
GREENISH GLAUCONITIC ARGILLACEOUS SAND WITH 
BAND OF CEMENT STONES ( CONTAINS CHALK FLINTS 
AND FRAGMENTS OF READING BED CLAY ) 



RED OCHREOUS SLUMPED BEDS CA 130' 



Fig. 5. Succession of the London Clay at Whitecliff Bay, showing the 
location of samples. 



22 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Studland Bay. One of the most westerly outcrops of the London Clay is found 
at Studland Bay in Dorset, where conditions in the Lower Eocene fluctuated between 
marine and fresh-water, being very close to, and at times marking, the shoreline of 
the London Clay sea. As with all cliff sections of the London Clay, difficulty is 
experienced in collecting because of slumping. This obscures most of the London 
Clay but fortunately both lower and upper junctions with the Reading and Bagshot 
Beds are exposed. 

Because of the poor exposures, samples could only be taken haphazardly, three 
(ST. 1-3) being collected within 10 feet of the base, and one (ST. 4) from only three 
feet below the junction with the Bagshot Beds. The London Clay at Studland is, 
at the base, an arenaceous yellow brown clay passing upwards into a friable yellow 
argillaceous sand ; the succeeding Bagshot Beds are almost pure quartz sands, 
bright yellow in colour and partly consolidated. 

Isle of Wight. The exposures of London Clay in the Isle of Wight at Alum 
Bay and Whitecliff Bay are of importance because they give the only continuous 
exposures through the whole London Clay, from the junction with the Reading Beds 
to the base of the Bagshot Sands. The dip of the beds is almost vertical and they 
strike at right angles to the exposure, thus providing comparatively easy conditions 
for collecting. The main difficulty is slumping or slipping, which is a common 
occurrence in the Alum Bay section, less frequent at Whitecliff. Only the White- 
cliff section has been studied because it is less affected by slumping and the junction 
of the London Clay and Bagshot Beds can be more precisely placed. 



Sheppey 




h 

Studland 



Whitecliff 



Fig. 6. Map of South-east England, showing in black the outcrop of the London Clay. 
The localities from which samples were collected are shown by the arrows. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 23 

According to the earliest authority on the Eocene of Whitecliff, Prestwich (1847), 
the thickness of his beds 3 and 4, (which he called the Bognor Beds), is 307 feet. 
These are equivalent to the London Clay. Bristow (1862) lists a succession but 
attempts no estimation of thickness. In the revised Isle of Wight Memoir of 1889, 
the section is not given in detail, but an approximate value of 320 feet for the thick- 
ness of the London Clay is quoted by Reid. The pebble bed according to Reid is 
255 feet above the base. The first detailed section is attributable to White (1921) 
who measured a total of 322 feet, with the pebble bed at 285 feet above the base. 
Since 1921 all authorities including Curry (1958a) have quoted this thickness of 322 
feet for the London Clay of Whitecliff. In measurements carried out by the authors 
with a tape measure a value of 300 feet was arrived at for the thickness of the 
London Clay with the pebble bed at 255 feet. Samples were taken for 315 feet above 
the base but the two topmost (305, 315 feet) were yellow sands barren of microplank- 
ton. 

Lithologically, the London Clay at Whitecliff is roughly divisible into three units 
equivalent to the Lower Silts, the Stiff Clays and the Upper Silts of the Enborne 
Valley (Hawkins 1954). Within each of these three units alternations of clays and 
sands with all degrees of intermingling often occur and septarian nodules, lignite 
and iron pyrites are common throughout. Sample numbers are shown in Text-fig. 5. 

Enborne Valley (Berkshire). In the years 1947-49 a series of borings were sunk 
in the eastern part of the Enborne Valley, penetrating beds primarily of Eocene age, 
much of which was London Clay. Professor H. L. Hawkins has kindly allowed us 
to take samples from cores in his possession. Two boreholes, numbers 11 and 39 
whose geographical positions can be seen in Text-fig. 6, were examined. 

According to Hawkins (1954), the London Clay of the Enborne Valley is litho- 
logically divisible into three sections, the Lower Silts, the Stiff Clays and the Upper 
Silts. 

From boring number 11, six samples have been examined in detail, one from the 
Upper Silts, four from the Stiff Clays and one from the Lower Silts. From boring 
number 39, four samples have been studied, three from the Stiff Clays, one from the 
Lower Silts. All the samples studied yielded microplankton usually in a good 
state of preservation (see Text-fig. 7). 

Sheppey. The London Clay attains its maximum thickness at Sheppey where 
Davis (1936) has estimated it to be 518 feet. Of this the upper 160 feet are exposed 
in the Sheppey cliff section running for six miles in an east-south-east direction from 
Scrapgate in the west to Warden Point in the east. The lithology is a uniform stiff 
blue grey clay with frequent courses of septaria. The junction with the Bagshot 
Beds is well exposed in the west where 10 feet of in situ Bagshot sand overlies the 
London Clay ; elsewhere difficulty is caused by large scale slipping and the number 
of samples collected is less than might have been desired. 

Wrigley (1924) proposed five divisions for the London Clay of the London Basin, 
each characterized by a faunal suite but not zones in the strictest sense. The fifth 
(uppermost) division is typically sandy with more frequent fossils than blue clay. 



24 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 27 

This uppermost division is represented at Sheppey by a continuation of the fourth 
division whose stiff clays with septaria come in 300-350 feet above the base. It is 
probable that most of the London Clay exposed at Sheppey falls within this (the 
fourth) division, the only possible exception being the " Foreshore Beds "of Davis 
(1936) which may mark the top of the third division. The first, second and most of 
the third divisions of Wrigley (1924) lying below the surface at Sheppey, only 
outcrop further east at Heme Bay and Reculver Bay, and are at present being 
investigated by Mr. A. Hussain in the Department of Geology at Sheffield University. 

Davis recognized the following sequences in the Sheppey cliff section : 

(d) Stiff brown clays with few fossils . . . . .50' 

(c) Stiff grey and brown clays with good fauna and flora in 

lower part. Rarely in situ. . . . . .60' 

(b) Stiff blue clays. Few fossils. . . . . .50' 

(a) Foreshore. Barren clays, blue or lead coloured. 

Group (a) The " Foreshore Beds ", probably include the upper parts of Wrigley 's 
third division, whilst beds (b), (c) and (d) seem to belong to his fourth division, (d) 
including the Sheppey equivalent of Wrigley's division five. Samples have only been 
collected from groups (a), (c) and (d) because group (b) was never clearly exposed 
(Text-fig. 7). 



28 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

IV. THE GENERA HYSTRICHOSPH A ERA AND A CHOMOSPH A ER A 

By R. J. DAVEY & G. L. WILLIAMS 

INTRODUCTION 

The celebrated German microscopist, C. G. Ehrenberg, was the first to notice the 
occurrence of minute spiny organisms in flakes of Upper Cretaceous flint. These 
organisms were divided by him into two types. The first type possessed oval to 
polygonal shells bearing numerous forked processes and characterized by two 
furrows, one encircling the shell and the other perpendicular to it on one surface 
only. Such forms he recognized as belonging to a group of present-day plankton, 
the dinoflagellates. The second type had spherical or oval shells bearing forked 
processes as before but not possessing furrows. These forms he found rather 
difficult to identify, but came to the conclusion that they were silicified zygospores 
of a freshwater desmid known as Xanthidium. His initial findings were published in 
1838 and 1843. 

In 1838 Ehrenberg came to England and visited the Clapham Microscopical 
Society where he greatly influenced a group of British microscopists — Mantell, 
Reade, Deane, White and Wilkinson. Mantell (1845), after critically examining the 
shells of the Xanthidia, came to the conclusion that they were composed of some 
flexible substance, probably organic, perhaps chitin or cutin. Later (1850) he 
suggested that the spiny spheres were " probably the gemmules of sponges or other 
zoophytes ", and proposed the new genus Spiniferites to include them. This new 
name, however, was overlooked by subsequent workers and was eventually abandoned 
as a nomen nudum (Sarjeant 1964). 

In 1904 the German marine biologist, Lohmann, after having worked on modern 
plankton and examined the fossil spiny spheres, decided that the latter were definitely 
planktonic. He came to the conclusion that they were eggs of a marine crustacean, 
probably a Copepod, and for this reason gave them the name Ova hispida. Reinsch 
(1905), for the first time, considered these fossils to be the cysts of marine algae, 
possibly dinoflagellates. He termed them " palinospheres ", another name which 
never came into general use. 

O. Wetzel (1933) rejected all previous attributions and placed them in a new 
family, Hystrichosphaeridae, of unspecified systematic position. All the described 
species were included in his new genus Hystrichosphaera, and Hystrichosphaera 
furcata and H. ramosa were designated as joint type species. 

Deflandre (1937) emended Wetzel's genus Hystrichosphaera to include only those 
forms possessing an equatorial girdle and polygonal fields. His choice of H. furcata 
as the sole type species has, however, proved an unfortunate one. Those forms 
without surface ornamentation he placed in a new genus, Hystrichosphaeridium 
Deflandre. 

Evitt (1961) considered that Hystrichosphaera was not a motile dinoflagellate but 
a cyst possessing structures which are reflections of features seen in the motile stage. 
The presence of a precingular archaeopyle was noted and compared with that present 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 29 

in Gonyaulacysta (Deflandre 1964). In 1963 he erected the genus Achmosphaera to 
accommodate species possessing a precingular archaeopyle and processes of the same 
form and distribution as found in the genus Hystrichosphaera, but lacking sutural 
crests or membranes. 

Genus HYSTRICHOSPHAERA O. Wetzel 1933 : 33 
1937. Hystrichosphaera O. Wetzel ; Deflandre : 61. 

Emended diagnosis. Chorate to proximo-chorate cysts possessing a sub- 
spherical or ovoidal central body with a clearly defined reflected tabulation of 
3-4', 6", 6c, 5'", o-ip, 1"", plate 6" being generally reduced and triangular. Wall of 
central body composed of two layers, an inner endophragm and an outer periphragm. 
Cingulum always disposed in a laevo-rotatory spiral. Plate boundaries indicated by 
variably developed sutural crests or membranes, and gonal and sutural processes. 
Processes open or closed, solid or hollow, simple or branching. Length of processes 
variable, sometimes not extending beyond sutural crests, apical pole often marked 
by an elongate process. Archaeopyle precingular, formed by loss of reflected plate 
3"- 

Type species. Xanthidium ramosa Ehrenberg 1838. Upper Cretaceous (Seno- 
nian) ; Germany. 

Remarks. The generic diagnosis is emended to include reference to the reflected 
tabulation and to the presence of sutural processes in many species attributable to 
this genus. 

The Hystrichosphaera furcata-ramosa complex 

It is difficult to distinguish between H. furcata (Ehrenberg) and H. ramosa (Ehren- 
berg). The original drawings of Ehrenberg are inadequate for the present refined 
morphological studies and there is no description accompanying the figures of the 
types. The types for both species have either been lost or have not been re-examined 
recently, and many varied interpretations of the species have been made by later 
workers. 

Ehrenberg (1838) figured a number of specimens as Xanthidium furcatum and 
Xanthidium ramosum without description or holotypes. His figures show that the 
main difference between the two species is the form of the extremities of the processes. 
X. furcatum has predominantly bifurcate processes ; only one of the figures (pi. 1, 
fig. 14a) shows trifurcate processes and then these do not predominate. X. ramosum 
has predominantly trifurcate processes and branching is shown to occur occasionally 
from a medial position on the processes. Branching is absent from Ehrenberg's 
figures of X. furcatum. The names given to the species confirm that Ehrenberg 
distinguished them on the type of process present. 

White (1842) published the first account of both species. X. furcatum he described 
as having numerous, regularly arranged processes which gradually taper distally ; 



30 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

thus they are not furcate. His figures are certainly not in accordance with those of 
Ehrenberg, and probably represent a different species. White's figures of X. 
ramositm closely resemble those of Ehrenberg for this species and are probably 
correct. The processes are predominantly trifurcate, often with a small bifurcation 
at their extremities. 

X. ramositm had been figured earlier, without description, by Reade (1839) but his 
figure more closely resembles X. complex White than Ehrenberg's figures of X. 
ramositm. Ehrenberg (1854) refigured some of his specimens but again they were 
not accompanied by a text description. 

O. Wetzel (1933) erected the genus Hystrichosphaera making both H. furcata and 
H. ramosa type species, this being contradictory to the rules of nomenclature. H. 
furcata is described as having strongly built processes with short bifurcations 
distally, each branch terminating in two spines. In H. ramosa some of the processes 
are divided into two, rarely more, they branch approximately half way along their 
length and finally divide into spinelets, usually three in number. The descriptions 
correspond with Ehrenberg's specimens, but O. Wetzel's plates are not distinct. 
Both species possess central bodies which are divided into fields or areas by sutures, 
from the junctions of which 6 to 30 processes arise. An equatorial girdle is often 
present. O. Wetzel considered H. furcata and H. ramosa to be varieties of the same 
species, and contrary to the rules of nomenclature, proposed a new name H. com- 
munis to contain them. 

Deflandre (1935, 1936) figured a specimen of H. furcata which differs from Ehren- 
berg's types in that there is a proximal membrane and the majority of the processes 
have trifurcate extremities. Later (1937) he published the first account of the 
tabulation of H. furcata and also mentioned the well developed apical process. He 
pointed out that the processes invariably arose from nodal points at the junction of 
the plates. The processes are short and predominantly trifurcate, although some 
bifurcate processes do occasionally occur. The number of processes is approxi- 
mately 30. The processes are not of equal length and tend to be shortest in the 
region of the triangular plate and longest at the poles. H. ramosa as figured by 
Deflandre differs from H. furcata only in the presence of processes which divide 
medially into two branches which themselves terminate distally in three spines. 
Like Wetzel Deflandre also considered H. furcata and H. ramosa to be varieties of 
one species, but suggested that the names H. furcata and H. furcata var. ramosa 
would be more appropriate, the latter being applied to individuals having slender 
and very divided processes. However the plates show only slight differences 
between the two types. Both possess bifurcate and trifurcate processes with medial 
branching and proximal membranes ; and considering the slenderness of the 
processes there is little or no difference. In fact both forms agree very well with 
X. ramositm of Ehrenberg. 

Lejeune (1937) re-examined Ehrenberg's preparations and rediscovered one of his 
figured specimens (pi. 1, fig. 1) of X. ramositm. A detailed description of H. ramosa 
was given by Lejeune accompanied by some excellent figures. The majority of the 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 31 

processes are trifurcate but some of the processes occupying a medial position are 
shown to be bifurcate. Some of the trifurcate processes possess small terminal 
bifurcations, and the membranes are always shown to be proximal. The number of 
processes is said to be approximately 40. Unfortunately, H. furcata was not 
similarly treated, Lejeune having apparently failed to recognize any of the original 
specimens figured by Ehrenberg as Xanthidium furcatum Ehrenberg. 

Valensi (1955) described forms in which the processes terminate in two small 
spines or a fork. However his figures do not always correspond to the description 
given. Some of the processes are open with serrate lips and others are trifurcate with 
distal bifurcations. Some of the specimens have prominent crests with elevated 
membranes and differ from both of Ehrenberg's forms. 

Eisenack (1958) described specimens attributed to H. furcata from the Aptian of 
Germany having short, thick processes with broad bases and dividing into two or 
three spines distally. In his description he emphasized the wide degree of variation 
in the species as interpreted by earlier workers. 

Maier (1959) described and figured H. furcata from the Miocene of Germany, her 
forms possessing solid processes which divide distally in two to four spines. Gocht 
(1959) described specimens of H. furcata from the Neocomian of Germany as some- 
times having isolated processes while others possessed well developed membranes 
along the plate boundaries uniting adjacent processes. H. ramosa, as described by 
Gerlach (1961), from the German Oligocene, possesses oval central bodies and 
trifurcate processes which are bifurcate distally. 

Brosius (1963) restricted H. furcata to forms with bifurcate and trifurcate processes 
and H. ramosa to those with trifurcate processes, each furcation terminating in a 
short bifurcation. Cookson & Hughes (1964) had difficulty in identifying H. 
ramosa in the Albian/Cenomanian of Cambridge and distinguished it from H. furcata 
by its larger size, thicker-walled processes, more strongly outlined fields and more 
pronounced membranes. 

Since the two species were first figured by Ehrenberg, there has been considerable 
difference of opinion as to how each species should be diagnosed, and subsequent 
authors appear to have attributed their specimens somewhat randomly to one, or more 
rarely, to both species. As Lejeune (1937) first pointed out with reference to these 
species in the Upper Cretaceous they, and closely related forms, form a continuous 
varying complex. One can treat such a complex in one of two ways. All described 
forms can be grouped under one species heading and varieties created or the group 
may be further subdivided, each new species being clearly defined. Detailed study 
of the Cenomanian and London Clay forms included within this complex rules out 
the adoption of the second alternative, since variation is so great as to render the 
interpretation of separate species, that would be of practical value, difficult if not 
impossible. 

One of the specimens designated as Xanthidium ramosum by Ehrenberg (1838, 
pi. 1, fig. 15) was located by Lejeune (1937). This specimen (refigured in pi. 1, 
fig. 1) and another of Ehrenberg's preparations have been fully studied by one of the 



32 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

authors (R.J.D.). The preparations, which are now in the Humboldt University, 
Berlin, were kindly lent for examination by Dr. K. Diebel whose assistance is 
gratefully acknowledged. 

Specimens of X. furcatum as illustrated by Ehrenberg (1838, pi. 1, figs. 12, 14) 
cannot be traced and are either not distinctive enough for sure identification with 
his drawings or they have subsequently been lost. It is therefore proposed to treat 
the complex as one species to be designated Hystrichosphaera ramosa, since none of 
the specimens of X. furcatum as figured by Ehrenberg has been positively identified 
by later workers. The specimen figured by Ehrenberg (1838, pi. 1, fig. 15) is erected 
as the holotype of H. ramosa and the species is regarded here as the type species of 
the genus. Since Ehrenberg did not designate a holotype or give a description of 
H. furcata, and since later workers have failed to recognize it, it is proposed that 
forms attributed to H. furcata since 1933 be transferred to H. ramosa Ehrenberg. 

Hystrichosphaera ramosa, in its revised acceptation, is an extremely long ranging 
species exhibiting a very considerable degree of variation in the detail of its mor- 
phology. Many of the extreme variants, encountered in isolation, would be con- 
sidered sufficiently morphologically distinct from the typical forms to justify their 
erection as separate species ; but consideration of the whole assemblage shows all 
intermediate stages to be represented. However, our present knowledge of the 
species suggests that particular variational trends may have occurred only at certain 
stages within the total range of the species ; the extreme variants are capable of 
ready recognition and may prove of value as stratigraphical indices. A number of 
varieties are therefore here proposed, distinguished on the bases of process number 
and form, combined with character of the periphragm. Each represents the extreme 
development of a particular structure or combination of structures ; intermediate 
stages to the typical H. ramosa var. ramosa are in all cases known and are even 
frequent, so that differentiation of these forms at a higher taxonomic level is con- 
sidered inappropriate. 

Hystrichosphaera ramosa (Ehrenberg) 

Emended diagnosis. A species of Hystrichosphaera possessing a thin walled 
central body, smooth, reticulate or granular. Gonal + sutural processes always 
extending beyond confines of sutural crests, solid or hollow, the latter closed distally. 
Typical gonal processes trifurcate, sutural processes bifurcate, both commonly 
terminating distally in a small bifurcation. 

Holotype. Slide "Feuerstein von Delitzsch, no. XXV" of Ehrenberg, Institut 
fur Palaontologie und Museum der Humboldt Universitat, Berlin. Upper Creta- 
ceous ; Germany. 

Stratigraphical range. This species has been recorded as H. furcata from the 
Oxfordian by Deflandre (1938) and Sarjeant (i960). Pleistocene examples have 
been observed by a number of workers, e.g. Fries (1951) and Rossignol (1964), and it 
has also been recorded from post-Pleistocene sediments dated 950 B.C. from West 
Wales. (Churchill & Sarjeant, in progress.) 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



33 



1838 
1838 
1854 
1854 
1932 
1932 

1935 
1936 
1937 
1937 
1937 
1941 

1947 
1947 
1952 
1952 
1964 



Hystrichosphaera ramosa (Ehrenberg) var. ramosa nov. 
PI. 1, figs. 1, 6 ; PI. 3, fig. 1 ; Text-fig. 8 

Xanthidium ramosum Ehrenberg, pi. i, figs, i, 2, 5. 
Xanthidium furcatum Ehrenberg, pi. 1, figs. 12, 14. 
Xanthidium ramosum Ehrenberg, pi. 7, figs. 9, 10. 
Xanthidium furcatum Ehrenberg, pi. 7, fig. 7. 
Hystrichosphaera furcata (Ehrenberg) O. Wetzel 
Hystrichosphaera ramosa (Ehrenberg) O. Wetzel 



Hystrichosphaera furcata (Ehr.) 
Hystrichosphaera furcata (Ehr.) 
Hystrichosphaera furcata (Ehr.) 
Hystrichosphaera ramosa (Ehr.) 
Hystrichosphaera ramosa (Ehr.) 
Hystrichosphaera furcata (Ehr.) 
Hystrichosphaera furcata (Ehr.) 
Hystrichophaera ramosa (Ehr.) 
Hystrichosphaera furcata (Ehr.) 
Hystrichosphaera ramosa (Ehr.) 
Hystrichosphaera furcata (Ehr.) 



136. 

144. 

Deflandre : 14, pi. 5, fig. 9 ; pi. 8, fig. 3. 
Deflandre : 62, text-fig. 108. 
Deflandre : 61, pi. n, figs. 1-3. 
Deflandre : 64, pi. 11, figs. 5, 7. 
Lejeune : 239, pi. 1, figs. 2-4 ; pi. 2, figs, 5-10. 
Conrad, text-fig. 2, no. 1. 
Deflandre : 22, text-fig. 1, no. 11. 
Deflandre : 22, text-fig. 1, no. 13. 
Deflandre, text-fig. 15. 
Deflandre, text-fig. 17. 
Cookson & Hughes : 45, pi. 9, figs. 1, 2. 



Diagnosis. A variety of H. ramosa possessing an ovoidal central body bearing 
gonal and occasionally a small number of sutural processes. Gonal processes 
triangular in cross-section, sutural processes taeniate. Distally the processes are 
trifurcate or bifurcate often with bifid terminations, tapering to sub-conical in 
shape and sometimes branched. Sutural crests between processes proximal. 
Tabulation typical for genus. 




Fig. 8. Hystrichosphaera ramosa var. ramosa (Ehrenberg). 

lateral view. x c.700. 



The holotype, in 



34 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Holotype. Slide " Feuerstein von Delitzsch, no. XXV " of Ehrenberg (ringed 
in white on the third slice of flint). Lodged at the Institut fur Palaontologie und 
Museum der Humboldt-Universitat, Berlin. Upper Cretaceous ; Germany. 

Dimensions. Holotype : diameter of central body 42 by 48^, length of processes 
I3~25(j.. Range of Lower Cretaceous (Barremian) specimens : diameter of central 
body 34-41^, length of processes 5-i3[x. Number of specimens measured, 2. Range 
of Cenomanian specimens ; diameter of central body 30-50^, length of processes 
7— 27JX. Number of specimens measured, 13. Range of London Clay (Ypresian) 
specimens ; diameter of central body 32-56{i., length of processes ii-20[jl. Number 
of specimens measured, 9. 

Description. The plates of the cingulum are distinctive, being elongate and 
six-sided. There are two gonal processes between adjacent cingular plates and 
these are usually connected by a well developed membrane. The longitudinal 
furrow is obvious and is considerably larger on the hypotract. A distinctive simple 
apical process is commonly present. When the trapezoid precingular archaeopyle is 
present it is noticeable that the margin appears to lie just within the boundary of 
plate 3". One specimen of H. ramosa var. raniosa (PI. 3, fig. 1) has been observed in 
the Upper Oxfordian (Throstler Clay, Upper Calcareous Grit) of England (Sarjeant 
i960). The specimen is large (central body diameter 58 by 61 jx, length of processes 
up to I9[x) but otherwise appears to be typical of this variety. 

This variety has a known stratigraphic range from the Middle Barremian to the 
Ypresian. 

Remarks. H. ramosa var. ramosa is characterized by the form of its processes 
and the absence or scarcity of sutural processes. Doubtful descriptions or illustra- 
tions of forms classified as H. furcata or H. ramosa have not been included in the 
synonymy of H. ramosa var. ramosa and are placed in H. ramosa (Ehrenberg) var. 
indet. The varieties of H. furcata described by Rossignol (1964) must be transferred 
to H. ramosa. 



Hystrichosphaera ramosa var. gracilis nov. 
PL 1, fig. 5 ; PL 5. fig- 6 

1955. Hystrichosphaera ramosa (Ehr.) ; Deflandre & Cookson : 263, pi. 5, fig. 8. 
1963. Hystrichosphaera ramosa (Ehr.) ; G6rka : 48, pi. 6, figs. 6, 7. 

Derivation of name. Latin, gracilis, slender or graceful — with reference to the 
slender, rather delicate processes. 

Diagnosis. A variety of H. ramosa (Ehrenberg) with smooth, thin-walled central 
body bearing gonal and sutural processes. Processes solid or hollow and relatively 
long and slender. Crests proximal and extending along all processes often as far as 
the trifurcation. Gonal processes mainly trifurcate, sutural processes bifurcate, all 
but smallest terminating with small trifurcation. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 35 

Holotype. B.M.(N.H.) slide ¥.51757(1). 5 feet above the base of London 
Clay ; Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 35 by 43fi., length of processes 
17-23^. Range of London Clay specimens ; diameter of central body 32-61- 5[x, 
length of processes up to 29[x. Number of specimens measured, 7. Range of 
Cenomanian specimens ; diameter of central body 28-33^, length of processes up to 
20;j,. Number of specimens measured, 3. 

Remarks. H. ramosa var. gracilis is characterized by the slender, relatively long, 
gonal and sutural processes. The position of the sutural processes in the examples 
studied appears to be haphazard. 

The known stratigraphic range of this variety is from the Cenomanian (England) 
to the Miocene (Australia). 

Hystrichosphaera ramosa var. granosa nov. 
PL 4, fig- 9 

Derivation of name. Latin, granosus, granular — with reference to the granular 
nature of the surface of the central body. 

Diagnosis. A variety of H. ramosa (Ehrenberg) similar to H. ramosa var. 
gracilis except that the surface of the central body is coarsely granular. Height of 
granules ranging up to o-5[x. 

Holotype. B.M.(N.H.) slide ¥.51752(2). 78 feet above the base of London 
Clay ; Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 35 by 42^, length of processes 
up to 19^. Range : diameter of central body 33-45^, length of processes up to 
io,[a. Number of specimens measured, 4. 

Remarks. A small number of specimens have been observed in the London 
Clay that apparently do not possess sutural processes. However, there is a com- 
plete gradation from these forms to those bearing many sutural processes and so 
separation solely on this characteristic was not thought to be practical. 

H. ramosa var. granosa has only been recorded from the London Clay of England. 

Hystrichosphaera ramosa var. multibrevis nov. 
PL 1, fig. 4 ; PL 4, fig. 6 ; Text-fig. 9 

1955. Hystrichosphaera furcata (Ehr.) ; Valensi : 586, pi. 4, fig. 4 ; pi. 5, fig. 12. 
1958. Hystrichosphaera furcata (Ehr.) ; Eisenack : 406, pi. 25, figs. 4-8. 

Derivation of name. Latin, multus, much; brevis, short — with reference to 
the large number of short processes present in this variety. 

Diagnosis. A variety of H. ramosa (Ehrenberg) with smooth or slightly reticulate 
central body bearing short solid processes less than half the diameter of central body 
in length. Gonal processes trifurcate, sutural usually bifurcate, both types usually 



36 



MKSOZOIC VXD CAINOZOIC DINOFLAGELLATE CYSTS 



terminating with a small bifurcation. Number and size of sutural processes varying 
considerably, up to three between adjacent gonal processes. Sutural crests proximal 
or well developed and always extending along gonal processes, making the latter 
subcorneal in shape. When the crests are well developed, the sutural processes may 
be reduced to delicate protuberances emanating from the crest border. 

Holotype. B.M.(N.H.) slide ¥.51981(1). Metropolitan Water Board Borehole 
No. 11 at 63 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 35 by 44-5^, length of 
processes up to 14^. Range of London Clay specimens ; diameter of central body 
35-59PL, length of processes up to i6}jl Number of specimens measured, 6. Range 
of Hauterivian and Barremian specimens ; diameter of central body 34-47^. 
Length of processes up to I2(x. Number of specimens measured, 7. Range of 
Cenomanian specimens ; diameter of central body 31-46^, length of processes up to 
i9[x. Number of specimens measured, 11. 

Remarks. H. ramosa var. multibrevis is characterized by the presence of short 
gonal and sutural processes. Examples from the Lower Cretaceous possess very 
short, rather rudimentary processes and differ from H. dentata (Gocht 1959) in 
having the characteristic tabulation of the genus which is lacking in Gocht's species. 
In the Cenomanian the processes are better developed but rather variable in form, 





Fig. 9. Hystrichosphaera ramosa var. multibrevis nov. A specimen from the London Clay. 
Left, ventral view. Plate 3" (the operculum of the archaeopyle) lies within the central 
body. Right, dorsal view. x c.1500. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 37 

stability being reached in the Eocene when the processes resemble those found in 
H. ramosa var. ramosa but are shorter and subconical, and considerably more 
numerous. H. ramosa var. multibrevis is similar to H . furcata var. multiplicata 
(Rossignol 1964) from the Pleistocene of the Eastern Mediterranean except for the 
absence of the two distinctive large dorsal antapical processes. 

H. ramosa var. multibrevis has been recorded from the Lower Cretaceous (Hauteri- 
vian) to the Eocene (Ypresian) in England, from the Upper Cretaceous of France and 
from the Aptian of Germany. 



Hystrichosphaera ramosa var. membranacea (Rossignol) 
PI. 4, figs. 8, 12 

1964. Hystrichosphaera furcata var. membranacea Rossignol : 86, pi. 1, figs. 4, 9, 10 ; pi. 3, 
figs. 7, 12. 

Material (Figured). B.M.(N.H.) slide ¥.51747(2). Metropolitan Water Board 
Borehole No. 11 at 53 feet depth, London Clay ; Enborne, Berkshire. Micropal. 
Lab., Sheffield University No. SL5. 173 ft. above base of London Clay ; Sheppey, 
Kent. 

Dimensions. ¥.51747(2) : diameter of central body 38- 5 by 43^, length of processes 
up to 19^. Observed range : diameter of central body 3i , 5-45f x < length of processes 
up to 26jjl. Number of specimens measured, 5. 

Remarks. The specimens belonging to this variety found in the London Clay 
agree fairly well with those observed by Rossignol (1964) from the Pleistocene. 
H. ramosa var. membranacea possesses a smooth walled central body with well 
developed membranes on the plate boundaries. The membranes are variable in 
height and development and may unite all or only few of the processes. However 
the membranes are commonly well developed only in the cingular and polar regions. 
The two large dorsal antapical processes noted by Rossignol are not noticeable in the 
Eocene forms. 

The often extensive development of a membrane in the equatorial zone restricted 
to one side gives some of the specimens a superficial resemblance to the form figured 
as H. ramosa by Lejeune (1937). 

Hystrichosphaera ramosa var. granomembranacea nov. 

PI. 4. ng. 4 

Derivation of name. Latin, granosus, granular ; membrana, membrane— 
with reference to the granular membranes present in this variety. 

Diagnosis. A variety of H. ramosa (Ehrenberg) possessing a central body with a 
granular surface. Membranes well developed on plate boundaries particularly in 
cingular and polar regions. 



38 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Holotype. B.M.(N.H.) slide ¥.51982(1). 99 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 47 by 49^, length of processes 
up to 20jx. Range : diameter of central body 41- 5-56^, length of processes up to 
27(1. 

Remarks. This variety is similar to H. ramosa var. membranacea except that the 
surface of the central body is granular ; it has only been recorded from the London 
Clay of England. 

Hystrichosphaera ramosa var. reticulata nov. 

PI. I, figS. 2, 3 

Derivation of name. Latin, reticulatus, net-like — with reference to the reticulate 
nature of the periphragm. 

Diagnosis. A variety of H. ramosa (Ehrenberg) with central body composed of 
thin smooth endophragm and reticulate periphragm. Gonal and occasionally 
sutural processes triangular, taeniate or subcorneal. Gonal processes trifurcate and 
suturals bifurcate, both types usually terminating distally with small bifurcation. 
Crests commonly reticulate, proximal except where they extend along processes. 

Holotype. Geol. Surv. Colin., slide PF.3038(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 750 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 36 by 42^, length of processes 
up to I4fx. Range : diameter of central body 33-59[i., length of processes up to 17^. 
Number of specimens measured, 13. 

Remarks. The processes, in the specimens possessing both gonal and sutural 
processes, are subcorneal. After further study these examples may be separated 
from the usual type of H. ramosa var. reticulata possessing only gonal processes. 
This variety is generally similar to H. ramosa var. ramosa but is readily distinguished 
by the reticulate surface of the central body. 

H. ramosa var. reticulata is present in small numbers throughout the Cenomanian 
of England. 

Hystrichosphaera cingulata (O. Wetzel) 
PI. 1, fig- 9 



1933 
1954 
1955 
1963 
1963 
1964 



Cymatiosphaera cingulata O. Wetzel : 28, pi. 4, fig. 10. 



Hystrichosphaera cingulata (O. Wetzel) Deflandre : 258. 

Hystrichosphaera cingulata (O. Wetzel) ; Deflandre & Cookson : 267, pi. 6, figs. 4, 5. 
Hystrichosphaera cingulata (O. Wetzel) ; Gorka : 51, pi. 6, figs. 8-10. 
Hystrichosphaera cingulata (O. Wetzel) ; Baltes : 587, pi. 4, figs. 12-17. 
Hystrichosphaera cingulata (O. Wetzel) ; Rossignol : 87, text-fig. G. 

Description. Examples of H. cingulata are common in the Cenomanian of 
England and are very similar to those described by Deflandre & Cookson (1955) and 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 39 

Gorka (1963). H. cingulata is characterized by well developed crests beyond which 
the gonal processes or thickenings do not protrude, the latter acting apparently only 
as supporting structures. The processes may be either simple or may terminate with 
a small bifurcation. The surface of the central body is smooth ; however the peri- 
phragm forming the crests may be slightly reticulate. The reflected tabulation is 
typical of the genus. 

H. cingulata has a stratigraphic range from the Cenomanian (England) to the 
Pleistocene (Eastern Mediterranean). 

Material (Figured). Geol. Surv. Colin., slide PF.3039(i). Lower Chalk, H.M. 
Geological Survey Borehole, Fetcham Mill, Surrey, at 730 feet depth. Upper 
Cretaceous (Cenomanian). 

Dimensions. Figured specimen : diameter of central body 37 by 39fi, height of 
crests up to i3[x. Range of Cenomanian specimens : diameter of central body 
26-48^, height of crests up to I3jx. Number of specimens measured, 15. 

Hystrichosphaera cingulata var. reticulata nov. 
PL 1, fig. 10 ; PI. 2, fig. 4 

Derivation of name. Latin, reticulatus, net-like — with reference to the reticulate 
nature of the periphragm. 

Diagnosis. A variety of H. cingulata with central body composed of smooth 
endophragm and strongly reticulate periphragm often somewhat thickened. Gonal 
" processes " not protruding above sutural crests, processes acting more or less as 
supporting structures for crests. Processes simple or terminating with small 
bifurcation. 

Holotype. Geol. Surv. Colin., slide PF. 3039(2). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 730 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 40 by 55[jl, height of crests 
up to i4fju Range : diameter of central body 33-59fx, height of crests up to \y\x. 
Number of specimens measured, 12. 

Remarks. This variety strongly resembles H. cingulata (O. Wetzel) but the 
central body has a strongly reticulate surface. Gorka (1963) states that many of the 
French examples of H. cingulata are lightly punctate and so may well belong to 
H. cingulata var. reticulata. 

H. cingulata var. reticulata occurs infrequently in the Middle and Upper Ceno- 
manian of England. 

Hystrichosphaera crassimurata sp. nov. 

PI. 1, fig. 11 

Derivation of name. Latin, crassus, thick ; murus, wall — with reference to the 
extreme thickening of the central body periphragm. 



40 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Diagnosis. A species of Hystrichosphaera with well developed crests. Gonal 
processes reduced to supports for crests. Periphragm of each reflected plate area 
smooth and extremely thickened. Reflected tabulation typical for genus. 

Holotype. Geol. Surv. Colin., slide PF.304o(i). Lower Chalk. H.M. Geologi- 
cal Survey Borehole, Fetcham Mill, Surrey at 670 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 44 by 46[x, height of crests up 
to I4fi. Range : diameter of holotype 36-46(1, height of crests up to 14(1. Number 
of specimens measured, 4. 

Description. Only gonal processes are present and these do not extend beyond 
the limits of the crests. The processes are usually simple but may terminate in a 
small bifurcation. The periphragm of the crests is typically slightly granular 
whereas that of the central body is always smooth. The thickened periphragm on 
the central body may be up to 3 - 5(x thick. 

This is a rare species, recorded only from the Middle and Upper Cenomanian of 
England. 

Remarks. High crests enclosing the processes are present in two other species of 
Hystrichosphaera : H. cingulata (Wetzel) and H. pterota (= Cymatiosphaera pterota 
Cookson & Eisenack). However H. crassimurata sp. nov. is readily distinguishable 
from these two species by the thickened areas of the periphragm on the central body. 



Hystrichosphaera crassipellis Deflandre & Cookson 
PL 1, figs. 7, 8 

1954. Hystrichosphaera crassipellis Deflandre & Cookson, text-fig. 5. 

1955. Hystrichosphaera crassipellis Deflandre & Cookson ; Deflandre & Cookson : 265, pi. 6, 
figs. 2, 3 ; text-fig. 20. 

1961. Hystrichosphaera crassipellis Deflandre & Cookson ; Gerlach : 177, pi. 27, fig. 5 ; 
text-figs. 16-18. 

Description. H. crassipellis possesses a thick central body wall (up to 6-5^. in 
thickness) which is coarsely reticulate. The reticulation is rather irregular having 
from almost circular to polygonal fields. The processes are gonal, subconical in 
shape and commonly bifurcate with bifurcating extremities. The paired cingular 
processes are joined by a membrane. The crests are proximal, reasonably well 
developed and may be reticulate, especially at their outer edges. H. crassipellis is 
a rare species occurring throughout the Cenomanian of England. 

Material (Figured). Geol. Surv. Colin., slide PF.3033(2). Lower Chalk, H.M. 
Geological Survey Borehole, Fetcham Mill, Surrey, at 730 feet depth. Upper 
Cretaceous (Cenomanian). 

Dimensions. Figured specimen : diameter of central body 45 by 4651, length of 
processes 12-15(1, overall diameter 64-67(1. Range of Cenomanian specimens : 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 41 

diameter of central body 34-68^, length of processes up to 26[x. Number of speci- 
mens measured, 16. 

Remarks. The Cenomanian specimens greatly resemble those of Deflandre & 
Cookson (1954, 1955) from the Lower Eocene of Australia, except that they are 
smaller. H. crassipellis as illustrated by Maier (1959) is very different and cannot 
be included within this species. 



Hystrichosphaera perforata sp. nov. 

PI- 5, fig- 7 
Derivation of name. Latin, perforatus, perforated — with reference to the 
perforate distal margins of the processes. 

Diagnosis. A species of Hystrichosphaera with smooth surfaced central body 
bearing both gonal and sutural processes. Processes either tri- or tetra-linguate, 
cylindrical and open with net-like perforations distally, or taeniate, being bi- or 
trifurcate distally. Medial branching of processes may occur. Tabulation typical 
of genus with plate 6" having a triangular outline. 

Holotype. B.M.(N.H.) slide ¥.51983(1). 85 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 40- 5 by 50, length of processes 
up to 26[x. Range : diameter of central body 28-50^, length of processes i^-26\i. 
Number of specimens measured, 4. 

Description. H. perforata sp. nov. is characterized by two types of processes : 
(1) gonal processes being open, cylindrical with tri- or tetra-linguate margins and 
possessing a triangular cross-section, and (2) taeniate processes being sutural in 
position. The processes are united by proximal membranes, of varying height, 
often with serrate edges, running along the plate boundaries. The open gonal 
processes are strongly fenestrate distally on the secae and occasionally along their 
length. A few of the processes are similar to those of H. ramosa var. ramosa in 
being closed distally. Each seca is usually distally bifid. The sutural processes are 
perforate distally where they bi- or trifurcate, and sometimes medially. 

Remarks. Two specimens of H. ramosa which were recorded by Gerlach (1961) 
possessed processes perforate distally and along their length. All the processes of 
these two specimens are, however, closed and the perforations are in the form of 
small circular holes and not net-like as in H. perforata. H. porosa (Manum & 
Cookson 1964) from the Upper Cretaceous of Canada possesses similar, but shorter 
and broader, perforate processes and a characteristic reflected tabulation— ri', 5", 
5c, 5'". I""- 



42 



MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 



Hystrichosphaera buccina sp. nov. 
PI. 4, fig. i ; Text-figs. 10, n 
Derivation of name. Latin, buccina, trumpet — with reference to the shape of 
the processes. 

Diagnosis. A species of Hystrichosphaera with central body composed of thick 
endophragm and thinner periphragm, the latter giving rise to gonal processes and 




Fig. io. Hystrichosphaera buccina sp. nov. Holotype, ventral view. x c.iooo. 





'# 



Fig. ii. Hystrichosphaera buccina sp. nov. A specimen from the London Clay, 

ventral view. x c.iooo. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 43 

proximal crests. Surface of central body slightly granular or rarely reticulate. 
Processes only gonal, simple or branched, and always open distally. Reflected 
tabulation is 3-4', 6", 6c, 5'", 1"". 

Holotype. B.M.(N.H.), slide ¥.51989(1). 106 feet above base of London Clay ; 
Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 58 by 62[i, length of processes 
up to 32(jl. Range : diameter of central body 54-68^, length of processes 24~36[x. 
Number of specimens measured, 4. 

Description. The endophragm of the central body is i - 5-2[x thick and the 
periphragm up to i[x. The processes terminate distally in three or more secae, 
which may be patulate, flaring or recurved. The tips of the secae may be oblate, 
bifid or bifurcate. This species occurs throughout the London Clay of England. 

Remarks. H. buccina sp. nov. is distinguished from all other species of Hystri- 
chosphaera, except H. tertiaria (Eisenack & Gocht), by the characteristic form of the 
processes. H. buccina differs from H. tertiaria in the tabulation, the latter reflecting 
5 precingular and 5 postcingular plates, 4 elongate rhombohedral cingular plates and 
a fifth triangular cingular plate. In H. buccina 6" is reflected and is triangular, 
whilst 6c runs along its antapical edge. Often the boundary between 6" and 6c is 
ill-defined and may only be seen at high magnification. H. tertiaria has only three 
apical plates whereas H. buccina may have 3 or 4. When 4 are present 1' and 4' are 
both narrow elongate plates and are in fine with the corresponding shortened sulcus. 
The processes of one of the London Clay specimens are reticulate or occasionally 
perforate, but their form is different from that of H. perforata sp. nov. 



Hystrichosphaera cornuta Gerlach 
PI. 4, fig. 7 ; Text-fig. 12 

1 961. Hystrichosphaera cornuta Gerlach : 180, pi. 27, figs. 10-12. 

Description. The specimens are identical to those described by Gerlach (1961) 
and possess the following reflected tabulation — 3-4', 6", 6c, 5'", ip, 1"", with plate 
6" triangular in outline. Whilst some species reflect only 3 apical plates, others 
show an elongate division of plate 1' to give rise to two plates which are in line with 
the sulcus. There is occasionally an apical bulge which interrupts the otherwise 
regular outline of the central body and lies immediately below the apical process. 
Gonal and sutural processes are present, and may occasionally be open. In some 
individuals the large apical process possesses small lateral spines. 

H. cornuta has only previously been recorded from the Middle Oligocene-Middle 
Miocene of N.W. Germany by Gerlach (1961). 

Material (figured). B.M.(N.H.) slide ¥.51741(2). 85 feet above base of 
London Clay ; Sheppey, Kent. 



44 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Dimensions. Figured specimen : diameter of central body 45 by 51(1, length of 
processes up to iiji, length of apical process 2511. Range : diameter of central 
body 39-52(1, length of processes 7-1311, length of apical process 20-26(1. Number 
of specimens measured, 5. 



Hystrichosphaera cornuta var. laevimura nov. 
PI. 4- %■ 5 

Derivation of name. Latin, laevis, smooth ; murus, wall — with reference to the 
smooth wall possessed by the central body in this variety. 

Diagnosis. A variety of H . cornuta (Gerlach) with smooth surfaced central body. 
Gonal and sutural processes short and subconical. A large distinctive apical 
process present often bearing small lateral spines. 

Holotype. B.M.(N.H.) slide ¥.51752(3). 78 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 43 by 53[i., length of processes 
up to 12(1. Range : diameter of central body 34-64(1, length of processes up to 14(1, 
length of apical process 16-32(1. Number of specimens measured, 4. 





Fig. 12. Hystrichosphaera cornuta Gerlach. A specimen from the London Clay. Left, 
ventral view, plate 3" (the operculum of the archaeopyle) lying within the central body ; 
right, dorsal view. x c.iooo. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 45 

Remarks. H. cornuta var. laevimura nov. differs from H. cornuta by possessing a 
central body with a smooth wall and is separated from this species because of the 
absence of intermediate forms with slightly granular walls. The apical bulge, 
occasionally found in H. cornuta, is also found in this variety. The processes of the 
latter are often more slender than those of H. cornuta but this feature is not charac- 
teristic. 

This is a rare form, only recorded from the London Clay of England. 



Hystrichosphaera cf. cornuta Gerlach 

Description. The central body of this form is slightly granular and bears very 
short gonal and sutural processes. The processes may be simple, bifurcate or 
trifurcate. A moderate sized apical process is present. 

Material. B.M.(N.H.) slide ¥.51985(1). 25 feet above base of London Clay ; 
Whitecliff Bay, Isle of Wight. 

Dimensions. ¥.51985(1) : diameter of central body 53 by 55^, length of pro- 
cesses up to 9[i, length of apical process i8[i. Range : diameter of central body 
3i-55fx, length of processes 4-9fx, length of apical process ii-i8fj.. Number of 
specimens measured, 3. 

Remarks. H. cf. cornuta from the London Clay appears to be transitional to 
H. speciosa (Deflandre 1934). The central body is less granular and the processes, 
particularly the apical one, are shorter than is normal in H. cornuta. The apical 
process, however, is similar in structure. 



Hystrichosphaera monilis sp. nov. 

PI. 5, ng. 2 

Derivation of name. Latin, monile, necklace or string of beads — with reference 
to the appearance of the sutural crests. 

Diagnosis. A species of Hystrichosphaera possessing a spherical central body with 
slightly granular surface. Processes short, sub-conical to cylindrical, closed, 
simple or distally forked. Granules concentrated along proximal sutural crests. 

Holotype. B.M.(N.H.), slide ¥.51986(1). 78 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 36 by 38^, length of processes 
up to iiji.. Range : diameter of central body 3i-46(x, length of processes up to ii[x. 
Number of specimens measured, 5. 



46 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. Distally the processes may be simple, bi- tri- or tetrafurcate. 
When the processes are furcate, the furcations are digitate and always erect. Each 
taeniate furcation may be bifid or have a serrate or entire distal margin. Some of 
the processes are fenestrate proximally. 

Remarks. The concentration of granules along the plate boundaries, the spheri- 
cal shape of the central body and the short erect processes differentiate H. monilis 
sp. nov. from all other described species of Hystrichosphaera. 

Hystrichosphaera sp. 

PL 9, fig. 9 

Description. A type of Hystrichosphaera with coarsely reticulate periphragm 
forming crests and processes, as well as surface of central body. The crests are well 
developed and bear small protruberances or stunted processes which terminate 
bluntly or are bifid. Gonal and a small number of sutural processes are present. 

Material (figured). B.M.(N.H.), slide ¥.51724(1). Speeton Clay, Shell West 
Heslerton Borehole at 42-5 metres depth, West Heslerton, Yorkshire. Lower 
Cretaceous (Lower Barremian). 

Dimensions. Figured specimen : diameter of central body 39 by 39^, length of 
processes up to iijx. Second specimen : diameter of central body 43 by 5i[x, 
length of processes up to I0[z. 

Remarks. This form has been encountered only rarely at one horizon, and it is 
characterized by its coarsely reticulate periphragm. It differs from H. ramosa in 
the reduced state of the processes and from H. cingulata var. reticulata in the presence 
of the latter. Since only two specimens were available for study and the presence of 
the typical Hystrichosphaera reflected tabulation was not verified. No specific name 
has been given. 

Genus ACHOMOSPHAERA Evitt 1963 : 163 

Diagnosis. Test consisting of spherical to ellipsoidal central body with pre- 
cingular archaeopyle and furcate, spine-like processes like those of Hystrichosphaera 
in both structure and distribution, but without sutural ridges or septa connecting 
their bases as in that genus. Tips of processes not connected. Wall two-layered ; 
layers typically in close contact between bases of processes. 

Type species. Hystrichosphaeridium ramuliferum Deflandre 1937. 

Remarks. One of the authors (R. J. D.) was allowed, by kind permission of 
Professor Deflandre, to examine the type material. One paratype, figured by 
Deflandre (1937, pi. 14, fig. 6), under high magnification was seen to possess very 
faint lines on the surface of the central body delimiting the plate boundaries. Such 
lines were not observed on the holotype but this was probably due to the obscuring 
nature of particles within the flint. These faint lines, slight thickenings of the 
periphragm and comparable to the sutural crests of Hystrichosphaera, have been 
observed in a number of chemically prepared specimens belonging to this genus. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 49 

Achomosphaera ramulifera (Deflandre) 
PL 2, fig. 3 



Hystrichosphaera cf. ramosa (Ehr.) ; Deflandre, pi. 5, fig. n. 

Hystrichosphaeridium ramuliferum Deflandre : 74, pi. 14, figs. 5, 6 ; pi. 17, fig. 10. 
Hystrichosphaeridium ramuliferum Deflandre ; Conrad : 2, pi. 1, fig. J. 
Hystrichosphaevidium ramuliferum Deflandre ; Pastiels : 39, pi. 3, figs. 17-19. 
Hystrichosphaeridium ramuliferum Deflandre ; W. Wetzel : 398, pi. A, fig. 9 ; text- 
fig- 9- 
Hystrichosphaeridium ramuliferum Deflandre ; Deflandre, text-fig. 4. 
Hystrichosphaeridium ramuliferum Deflandre ; Valensi : 594, pi. 4, fig. 6. 
Hystrichosphaeridium ramuliferum Deflandre ; Gocht : 71, pi. 3, fig. 9. 
Hystrichosphaeridium ramuliferum Deflandre ; Baltes : 586, pi. 7, figs. 13, 17, 18. 
Hystrichosphaeridium ramuliferum Deflandre ; G6rka : 59, pi. 8, fig. 3 ; text-fig. 6, 

figs- 3. 4- 
Baltisphaeridium ramuliferum (Deflandre) Downie & Sarjeant : 92. 
Achomosphaera ramulifera (Deflandre) Evitt : 163. 



Description. Representatives of this species occur infrequently in the Ceno- 
manian of England and are very similar to the type material. The central body is 
smooth or very slightly reticulate and upon it may be traced lines marking the 
reflected plate boundaries. The processes are hollow, often possessing rather 
bulbous bases, and having usually trifurcate with bifurcating extremities. The 
cingular processes are commonly joined and a distinctive apical process is usually 
present. The London Clay forms attributed to A. ramulifera often differ from the 
type material in having processes with more than three furcations, exceptionally 
six spines arising from one process . When six spines are present , they have apparently 
resulted from the elongation of the bifid tips of the three original furcations. Pastiels 
(1948) also recorded forms from the Ypresian of Belgium which may have more than 
three spines arising from a single process. The surface of the central body may be 
smooth or slightly granular. 

The species has a stratigraphic range from the Cenomanian to the Middle Miocene. 

As with Hystrichosphaera ramosa, A. ramulifera is probably divisible into a number 
of varieties ; one obvious variety would be those forms possessing multifurcate 
processes as opposed to the trifurcate processes of the type material. In the present 
state of knowledge, however, it is better to proceed cautiously in the erection of 
varieties, since too few specimens have been studied for an adequate picture to have 
emerged. 

Dimensions. Cenomanian forms : diameter of central body 40-56^, length of 
processes up to 36(0.. Number of specimens measured, 4. London Clay forms : 
diameter of central body 24-541;., length of processes up to 35fi.. Number of speci- 
mens measured, 10. 



5o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Achomosphaera ramulifera var. perforata nov. 
PI. 5, figs, i, 4 

Derivation of name. Latin, perforatum, perforated — with reference to the 
perforate nature of the processes. 

Diagnosis. A variety of A. ramulifera with gonal processes fenestrate proximally 
and sometimes distally. 

Holotype. B.M.(N.H.) slide ¥.51764(1). 14 feet above base of London Clay ; 
Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 33 by 42^, length of processes 
i6-i8[j.. Range : diameter of central body 33-56^, length of processes 15— 26jjl. 
Number of specimens measured, 3. 

Remarks. The forms placed in A. ramulifera var. perforata differ from the 
typical A. ramulifera by the presence of perforate processes. This characteristic 
was not thought distinctive enough to justify the creation of a new species. 

This variety occurs infrequently in the London Clay (Ypresian) of England. 



Achomosphaera alcicornu (Eisenack) 
PI- 5, ng. 3 

1954. Hystrichosphaeridium alcicornu Eisenack : 65, pi. 10, figs. 1, 2 ; text-fig. 5. 
1 961. Hystrichosphaeridium alcicornu Eisenack : Gerlach : 188-189, pi- 28, fig. 7. 

Description. The London Clay specimens are very similar to H. tertiaria 
(Eisenack & Gocht) and differ only in the absence of clearly defined plate boundaries. 
A precingular archaeopyle is present. That the archaeopyle is precingular is 
determined by its shape and the presence of 5 surrounding processes. The apical 
process and the cingular processes are typically branched. As in all species of 
Achomosphaera only gonal processes are present. The occasional specimen in the 
London Clay is slightly granular and some possess processes that are perforate 
distally. 

Material (figured). B.M.(N.H.) slide ¥.51765(1). Metropolitan Water Board 
Borehole No. 11 at 83-25 feet depth. London Clay : Enborne, Berkshire. 

Dimensions. Figured specimen : diameter of central body 54 by 54[x, length of 
processes 28-40^. Range : diameter of central body 49-66^, length of processes 
24-46PL Number of specimens measured, 4. 

Remarks. The stratigraphic range of A. alcicornu is from the Eocene (Ypresian) 
to the Middle Miocene (Gerlach 1961). 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 51 

Achomosphaera sagena sp. nov. 
PI. 2, figs. 1, 2 

Derivation of name. Latin, sagena, fish-net — with reference to the distinctive 
net-like pattern on the surface of the central body. 

Diagnosis. Wall of central body extremely thick, apparently composed of 
columar elements, surface coarsely reticulate. Closed gonal processes hollow, 
trifurcate with bifurcate extremities, and commonly possessing reticulate bases. 
Processes sometimes branched, branding mainly confined to cingular zone. Charac- 
teristically shaped precingular archaeopyle often present. 

Holotype. Geol. Surv. Colin, slide PF.304i(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 650 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 48^, length of processes up to 
20pL. Range : diameter of central body 35-59^, length of processes up to 28[x. 
Number of specimens measured, 8. 

Description. The wall of the central body, which may be up to 5\l thick, is 
composed of elongate cellular elements lying perpendicular to the surface. The 
surface reticulation is coarse and may be up to i*5[x across (PI. 2, fig. 2). 

A . sagena sp. nov. has only been recorded from the Cenomanian of England. 

Remarks. A. sagena is similar to H. crassipellis (Deflandre & Cookson) in that 
both possess thick walls of an identical nature with a reticulate surface. However 
sutural crests are absent in A . sagena. 



Achomosphaera neptuni (Eisenack) 
PL 3, fig. 7 ; PL 9, fig. 11 

1958. Baltisphaeridium neptuni Eisenack : 399, pi. 26, figs. 7, 8 ; text-fig. 8. 

1959. Baltisphaeridium neptuni Eisenack ; Gocht : 73, pi. 4, fig. 14 

Description. A. neptuni possesses a central body with a reticulate or sometimes 
slightly fibrous surface. The processes are gonal in position, taeniate or taeniate- 
triangular and may be bifurcate or trifurcate. In the cingular zone the processes 
are branched. The processes are fibrous, the fibres sometimes radiating from the 
bases of the processes and these may be slightly thickened along the reflected plate 
boundaries joining the processes. A precingular archaeopyle is often present. 

Material (figured). B.M.(N.H.) slides V.51716-17. Speeton Clay, Shell West 
Heslerton boring at 103-25 metres depth, West Heslerton, Yorkshire. Lower 
Cretaceous (Middle Hauterivian). 

Dimensions. V.51716, diameter of central body 61 by 66\i, length of processes 
up to 28(x. V.51717, diameter of central body 47 by 52^, length of processes up to 

2I(Jl. 



5-' MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Remarks. The Hauterivian examples strongly resemble those forms illustrated 
by Eisenack (1958) from the Aptian of Germany. In both of Eisenack's photographs 
(pi. 26, figs. 7 and 8) the views are either apical or antapical, a rather misleading 
orientation, the archaeopyle being seen in profile on the top side of these figures. 
The antapical view is shown in one of the specimens figured here, pi. 3, fig. 7, the 
archaeopyle being to the north-east. The processes of A . neptuni are very character- 
istic and it should be noted that they are not distally bifurcate as is usual in this 
genus and in Hystrichosphaera. 

OTHER S PECIES 

Achomosphaera hyperacantha (Deflandre & Cookson). This species, Hystricho- 
sphaera hyperacantha Deflandre & Cookson 1955, which possesses very faint or 
invisible plate outlines is here considered to belong to the genus Achomosphaera 
Evitt and is renamed accordingly. Miocene ; Australia. Achomosphaera triangu- 
lata (Gerlach 1961 : 194, pi. 29, fig. 1) is here transferred to Achomosphaera on the 
basis of the possession of a precingular archaeopyle and the arrangement of the 
processes. Miocene ; Germany. 

CONCLUSIONS 

The characteristics and known stratigraphical distribution of the species and 
varieties of the genus Hystrichosphaera are summarized in the accompanying table 
(Table 2). The varieties of H. ramosa, as has been previously pointed out, are 
intergrading and, as one would expect, no clear stratigraphical picture emerges. 
The more distinctive species of this genus, when better known, may be of some 
stratigraphic value. For instance H. crassipellis (Deflandre & Cookson) has not been 
recorded from deposits earlier than the Cenomanian, nor has it been recorded from 
the Ypresian of England. Thus its stratigraphic range appears limited. Similarly 
H. cornuta (Gerlach) has not been recorded from deposits earlier than Tertiary. 

Species of Hystrichosphaera are extremely rare in the Upper Jurassic, becoming 
more common in the Lower Cretaceous and from the Upper Cretaceous to the 
present day are an important constituent of the dinoflagellate cyst population. 
Variation has, however, been on a rather limited theme so making species differen- 
tiation extremely difficult. Moreover there appears to be a complicated plexus of 
evolution, particularly noticeable in the H. ramosa group. More detailed studies in 
the future may, however, throw light on some of these problems and aid the syste- 
matist and the stratigrapher. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 53 

V. THE GENUS HYSTRICHOSPHAERIDIUM AND ITS ALLIES 

By R. J. DAVEY & G. L. WILLIAMS 

INTRODUCTION 

The early history of the study of fossil dinoflagellate cysts, first described by 
Ehrenberg (1838), is discussed in the previous chapter. 

White (1842) was the first to describe the forms possessing tubular processes in his 
section on types of Xanthidia tubifera. In 1933, O. Wetzel placed all the then 
regarded species of fossil microplankton in the new genus Hystrichosphaera. Deflan- 
dre (1937) subdivided this genus separating those forms possessing an equatorial 
girdle and polygonal fields, which he placed in the genus Hystrichosphaera emend., 
and those without surface ornamentation which he placed in a new genus Hystri- 
chosphaeridium. The diagnosis of the genus Hystrichosphaeridium was given as 
follows : " This genus comprises all the hystrichospheres totally destitute of an 
equatorial system of elongate plates and whose shell, in general, does not bear 
fields or plates limited by sutures. The shell, of dimensions greater than 20[x, is 
most often spherical or spheroidal ; some species, however, are more or less elongate." 

Eisenack (1958) emended and restricted this genus as follows : " Hystricho- 
spheres with spherical to oval, non-tabulate central shell and with more or less 
numerous, mostly well separated and in general similar appendages, the ends 
being open and often expanded in funnel-like fashion." Those species not included 
in Hystrichosphaeridium by Eisenack have been revised by Downie & Sarjeant 
(1963)- 

Before classification of the spiny spheres placed in the genus Hystrichosphae- 
ridium Deflandre could be attempted with any precision, their affinities had to be 
determined. Certain organisms such as forms belonging to the genus Gonaulacysta, 
are associated with species placed in Hystrichosphaeridium, and have a similar two 
layered body-wall apparently composed of the same or a very similar organic 
substance. These organisms are obviously related to the dinoflagellates and are 
either resting or reproductive cysts. They possess a characteristic ornamentation 
which can be related to the theca of modern dinoflagellates ; for example the 
crests marking the tabulation as seen in Gonyaulacysta and Hystrichosphaera or less 
obvious the distinctive equatorial region as possessed by Deflandrea or Palaeo- 
hystrichophora. 

Thus many forms of fossil microplankton could definitely be said to be cysts of 
dinoflagellates, but what of the genus Hystrichosphaeridium ? Numerous forms had 
been attributed to this genus but dinoflagellate features had not been definitely 
noted in any of them. In fact they appeared to be simple spherical shells possessing 
a number of randomly arranged tubular appendages, usually with an opening or 
pylome of some kind which no doubt was used by the organisms as an exit. It was 
not until 1961 that Evitt pointed out the importance of these openings. He drew 
attention to the fact that most of the openings had angular margins and realized that 
here was evidence of breakage along a definite line. These openings, or " archaeo- 



54 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

pyles " as he called them, were not irregular ruptures of a cyst wall but within a 
species were of constant shape and size. In forms that are definitely cysts of 
dinoflagellates, archaeopyles are formed by the loss of areas which correspond to a 
single plate or plates of the original dinoflagellate theca. Four types of archaeopyle 
were differentiated by Evitt. They are the precingular and intercalary archaeopyles, 
each formed by the loss of one plate ; the apical archaeopyle formed by the loss of 
the apical region, commonly four plates ; and the epitractal archaeopyle formed by 
the loss of the whole of the epitract above the girdle. Examination of species from 
the genus Hystrichosphaeridium reveals that the archaeopyle is practically always 
apical for three reasons : 

(i) Surrounding the archaeopyle, in forms possessing less than 30 processes, 
there are constantly six processes corresponding to six precingular plates ; 

(2) The detached operculum frequently bears four processes, reflecting the 
four apical plates found in many dinoflagellates ; 

(3) In ovoidal or elongate forms the archaeopyle is usually formed at one of the 
extremities. 

It was discovered in a number of forms, for instance H. tubiferum (Ehrenberg), that 
there was an obvious circular arrangement of the processes around the central body 
of the cyst, and that the number of processes was equal to the number of plates 
possessed by forms having a typical Gonyaulax-type tabulation. Thus in the above 
forms, one process on the central body of the cyst reflects one plate in the dino- 
flagellate theca, the process extending from the cyst to the centre of the plate. 
Such processes are referred to as being intratabular and from them may be calculated 
the original tabulation of the dinoflagellate. 

Apart from the apical archaeopyle other features may be used in the orientation of 
the specimen and the elucidation of the process arrangement. Although the 
processes may all be of the same type, the sulcal processes, like the corresponding 
plates, are usually relatively small in size. The ant apical process and the cingular 
processes usually expand to some extent and terminate with a spinous or serrate 
margin. The spines become finer away from the process margin and it is very 
easy to imagine a plate affixed to such a process termination. 

All the above points seem to indicate conclusively that forms belonging to the 
genus Hystrichosphaeridium are cysts of dinoflagellates. The cysts are formed 
within dinoflagellate thecae, during or as a response to adverse conditions, the 
processes acting as pillars between the cyst and the thecal wall, and holding the cyst 
in position. Subsequently to the cyst formation the dinoflagellate theca is lost, the 
latter only very rarely being observed in preserved material. Sarjeant (1965, 
text-fig. 3) tentatively reconstructed the original tabulation of a dinoflagellate theca 
from the distribution of the processes for the species, Oligosphaeridium vasiformum 
(Plate 9, fig. 7). 

Evitt (1961) suggests that there were three main divisions in the genus Hystri- 
chosphaeridium : those forms possessing cingular or girdle processes of similar form 
to the other processes, those with distinct, often more slender, cingular processes and 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 55 

those forms having a cingular region devoid of processes. He concludes that the 
character of the cingular processes, or their absence, is of taxonomic importance and 
could be used in the subdivision of this genus. 

During a revision of the genus Hystrichosphaeridium it was noticed that most of 
the species could be placed in well-defined groups based primarily on the type of 
archaeopyle, the number of processes on the apical region and the overall number of 
processes on the central body. Forms possessing an apical archaeopyle and one 
process per plate may have either one, three or four apical processes, the familiar 
type of Hystrichosphaeridium possessing four apical processes. Subdivision of this 
group was made on the presence or absence and type of cingular process. The 
genus Hystrichosphaeridium is emended to restrict it to forms possessing normal 
tubular cingular and sulcal processes. These forms possess a process arrangement 
reflecting a certain tabulation, that is characterized by the type species H. tubiferum 
(Ehrenberg) — 4'(— 5'), 6", 6c, 5-6'", ip, 1"" and a variable number of sulcal proces- 
ses. Forms where the cingular processes are absent are placed in a new genus 
Oligosphaeridium. A third genus, Perisseiasphaeridium gen. nov., is erected to 
contain forms somewhat intermediate between the previous two genera, possessing 
cingular and sulcal processes not of the normal tubular type, but smaller and usually 
closed. 

The genus Litosphaeridium gen. nov., is characterized by the possession of three 
apical processes and the absence of cingular processes. Finally in this group 
possessing an apical archaeopyle and one process per plate is the genus Cordon- 
sphaeridium (Eisenack) which is characterized by having an archaeopyle formed by 
the loss of a single apical plate. 

Two new genera possessing an apical archaeopyle but more than one process per 
plate are erected. Polysphaeridium gen. nov., possesses numerous processes all of 
the same type (Diphyes is easily distinguishable by the presence of a large antapical 
process) and Tanyosphaeridium gen. nov. possesses an elongate central body and at 
the antapex probably 3 to 6 antapical processes. 

Two new genera have been erected possessing an epitractal archaeopyle. Homo- 
tryblium gen. nov. possesses tubular processes of a more or less constant size, there 
being three apical processes. The presence of three apical processes may indicate a 
relationship with Litosphaeridium gen. nov., however cingular and sulcal processes 
are well developed in Homotryblium whereas in Litosphaeridium they are absent or 
very reduced. The other genus possessing an epitractal archaeopyle is Callaio- 
sphaeridium gen. nov. which is represented by only one species, C. asymmetricum 
(Deflandre & Courte ville) . It is extremely distinctive, possessing both solid and 
tubular processes, one or perhaps two, apical processes and no antapical processes. 

Genus HYSTRICHOSPHAERIDIUM Deflandre 1937 : 68 
1958. Hystrichosphaeridium Deflandre ; Eisenack : 399, 400. 

Emended diagnosis. Subspherical chorate cysts possessing a reflected tabulation 
of 4' (-5'), 6", 6c, 5-6'", ip, 1"" and a variable number of sulcal processes. Processes 



56 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

hollow, open distally, intratabular, one process per plate area. Number of processes 
rarely exceeding 30. Archaeopyle apical. 

Type species. Xanthidium tubiferum Ehrenberg 1838. Upper Cretaceous ; 
Germany. 

Remarks. The central body is composed of two membranes, an inner endo- 
phragm and an outer periphragm, the latter also comprising the processes. In 
contrast to the genus Oligosphaeridium, the genus Hystrichosphaeridium posseses 
6 cingular processes. The cavities of the processes are never in contact with the 
interior of the central body. The sulcal processes of this genus are often noticeably 
smaller than the other processes which are approximately of the same size, except 
for the antapical process which may be larger. 

The above emendation restricts the genus Hystrichosphaeridium to those forms 
possessing the given tabulation and open processes. Other forms possessing open 
processes and formerly included in Hystrichosphaeridium have been placed in new 
genera according to the type of archaeopyle, the tabulation, the number and form 
of the processes and the shape of the central body. 



Hystrichosphaeridium tubiferum (Ehrenberg) 
PI. 6, figs. 1, 2 ; PI. 8, fig. 5 ; PI. 10, fig. 2 ; Text-fig. 13 



1838 
1848 

1854 
1904 

1933 
1937 

1940 
1941 
1952 
1963 



Xanthidium tubiferum Ehrenberg, pi. 1, fig. 16. 

Xanthidium tubiferum Ehrenberg ; Bronn : 1375, pi. 1, fig. 16. 

Xanthidium tubiferum Ehrenberg ; Ehrenberg, pi. 7, fig. 48 ; pi. 37, fig. 7, no. 11. 

Ovum hispidium (Xanthidium tubiferum) Ehrenberg ; Lohmann : 21. 

Hystrichosphaera tubifera (Ehrenberg) O. Wetzel : 40, pi. 4, fig. 16. 

Hystrichosphaeridium tubiferum (Ehrenberg) Deflandre : 68. (The specimens figured 

are of H. recurvatum.) 
Hystrichosphaeridium tubiferum (Ehrenberg) ; Lejeune-Carpentier : 218, figs. 1-4. 
Hystrichosphaeridium tubiferum (Ehrenberg) ; Conrad, pi. iF, fig. 2F. 
Hystrichosphaeridium tubiferum (Ehrenberg) ; Gocht, pi. 1, fig. 4. 
Hystrichosphaeridium tubiferum (Ehrenberg) ; Gorka : 55, pi. 8, figs. 1, 2 ; text-pl. 6, 

figs. 1, 2. 



Emended diagnosis. Central body spherical to subspherical, smooth or slightly 
granular wall composed of two layers. Processes well developed, tubiform, open 
distally with entire or serrate circular margin. Processes give a reflected tabulation 
of 4-5', 6", 6c, 5-6'", ip, 1"" and a variable number of sulcal plates, commonly 4-5. 
Apical archaeopyle usually present. 

Holotype. Slide XXV in a series of flints from Delitzsch, Institut fur Palaonto- 
logie u. Museum der Humboldt-Universitat, Berlin. 

Dimensions. Holotype: diameter of central body 33 by 34^, length of processes 
27-29^, number of processes 24. Paratype : diameter of central body 33 by 36^, 
length of processes 19-22(1. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



57 



Description. Central body composed of thin smooth endophragm and smooth 
or slightly granular periphragm, the latter also forming the processes. The processes 
are tubiform with distally a denticulate to serrate circular margin. At the base of 
each process is a characteristic circular mark caused by the initial divergence of the 
endophragm and periphragm. The processes, up to 30 in number, are usually 
shorter in length than the small diameter of the central body. They are of unequal 
width, the sulcal processes being finer and usually shorter. Lejeune-Carpentier 
(1940), after examination of the type material, records that this species is common 
from the Upper Turonian and Senonian. 

The processes of the London Clay specimens often possess unusual foliaceous 
outgrowths emanating from the margin and these may be diagnostic enough to 
differentiate Eocene forms from Upper Cretaceous forms. All the London Clay 
forms have at least 20 processes. 10 specimens were measured, the diameter of the 
central body being 28-53fx and length of processes i^-2g\i. 

H. tubiferum is uncommon in the Cenomanian of Fetcham Mill (Surrey) and is 
rather variable in the form of its processes. Specimens which closely resemble the 
holotype have been observed, the sulcal processes, however, being less noticeably 
small. At the base of the Cenomanian the processes of H. tubiferum expand distally 
and terminate in a denticulate margin, a few short secae are often present. Towards 
the top of the Cenomanian the processes do not expand so much and the secae are 
more pronounced and isolated. Diameter of central body 30-51(1, length of processes 
15— 37(x, 26 specimens being measured. 




^ 




Fig. 13. Hystrichosphaeridium tubiferum (Ehrenberg) . A specimen from the London 
Clay. Left, apical view showing the archaeopyle, precingular and cingular processes, 
and a single sulcal process ; right, antapical view (by transparency) showing the pre- 
cingular, sulcal, posterior intercalary and antapical processes. x c. 1000. 



58 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Discussion. H. tiibiferum has been recorded many times but often incorrectly. 
The specimens figured by Reade (1839, pi- 9> n S s - 6, 19) and Deflandre (1937, pi. 12, 
fig. 14 ; pi. 13, figs. 2, 14) show all the characteristics of Hystrichosphaeridium 
recurvation (White) and should be regarded as attributable to this species. H. 
tubiferum (Valensi, 1955, pi. 4, fig. 2 ; pi. 5, fig. 8) may also belong to H. recurvatum. 

The specimens illustrated by Eisenack (1958, pi. 25, fig. 16) and Pocock (1962, pi. 
15, fig. 230) should probably be referred to Oligosphaeridium complex (White). 

A number of other specimens have been referred to H. tubiferum but their true 
systematic position is doubtful, and almost certainly they do not belong to this 
species. 

Hystrichosphaeridium tubiferum (Ehrenberg) var. brevispinum nov. 

PL 10, fig. 10 

Derivation of name. Latin, brevis, short ; spina, spine — referring to the short 
processes. 

Diagnosis. A variety of Hystrichosphaeridium tubiferum with processes rarely 
exceeding one-third of the diameter of the central body. 

Holotype. B.M.(N.H.) slide ¥.51738(1). Metropolitan Water Board Borehole 
No. 39, at 160 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 32 by 36^ ; length of 
processes up to iiji. ; width of processes up to iijjl ; number of processes 23. 
Range : diameter of central body 3i-53[x ; length of processes 6-1 ijx ; width of 
processes up to I3[i. ; number of specimens measured, 7. 

Remarks. This variety forms a distinct group distinguishable from Hystri- 
chosphaeridium tuberiferum only by the length of the processes. It differs from 
? Hystrichosphaeridium arundum (Eisenack & Cookson i960) from the Lower Creta- 
ceous of Australia, by having much broader processes. 

Hystrichosphaeridium deanei sp. nov. 
PL 6, figs. 4, 8 

Derivation of name. Named in honour of H. Deane, an early worker on fossil 
microplankton from the Chalk of England. 

Diagnosis. Subspherical to ovoidal central body composed of thin smooth 
endophragm and smooth or slightly granular periphragm, the latter forming the 
processes. Tubular processes varying considerably in shape, sub-conical, lagenate 
or tubiform, open distally with entire or serrate margins. Width of processes 
extremely variable. Apical archaeopyle usually present. 

Holotype. Geol. Surv. Colin, slide PF. 3030(1). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 690 feet depth. Upper Cretaceous 
(Cenomanian). 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 59 

Dimensions. Holotype : diameter of central body 46 by 4J\l ; width of antapical 
process 31^, length 35fx ; length of other processes 15-30E1. Number of processes 
21. Range : diameter of central body 41-5411, length of processes i5-45jx. Num- 
ber of specimens measured, 9. 

Description. The endophragm of the processes may be fibrous, but not strongly 
so. The processes vary greatly in size and shape, this variation being continuous 
between extremes of the range. The width of the processes on a specimen may vary 
from i-5[x to 35^ ; the length of the processes is, however, more constant. The 
largest process is usually the antapical, it being sub-conical to lagenate in shape. In 
one specimen only a few of the larger processes are seen to give rise to two or three 
parallel branches distally. The processes reflect a tabulation of 4', 6", 6c, 5'", ip, 
1"" and 2-4S. 

H. deanei has been recorded from the Middle and Upper Cenomanian of Fetcham 
Mill, Surrey. 

Remarks. H. deanei sp. nov. resembles H. stellatum (Maier) recorded from the 
Albian and Cenomanian of Australia by Cookson & Eisenack (19626). It is similar 
in the general form of the processes and the size of the central body, but the sub- 
conical to lagenate processes, common in the British forms, appear to be absent. 
The Australian form of H. stellatum does not appear to be comparable to Maier's type 
material from the Oligocene of Germany. 

The form and the distal margins of the processes differentiate H. deanei from 
H. tubiferum. The reflected tabulation, however, reveals a fairly close relationship 
between the two species. 



Hystrichosphaeridium simplicispinum sp. nov. 
PI- 9, ng. 3 

Derivation of name. Latin, simplicis, simple or straight and spinous, thorny — 
referring to the rather simple nature of the processes. 

Diagnosis. Spherical central body composed of thin smooth endophragm and 
periphragm, the latter forming the processes. Processes varying considerably in 
size and are simple, tubiform, splaying out distally and terminate with denticulate or 
secate margin. A number of fine sulcal processes. Apical archaeopyle usually 
present. 

Holotype. B.M.(N.H.) slide ¥.51729(2). Speeton Clay, Shell West Heslerton 
Borehole No. 1, Yorkshire at 39 metres depth. Lower Cretaceous (Middle Barre- 
mian). 

Dimensions. Holotype : diameter of central body 36 by 43[x, length of processes 
iy-26[i. Number of processes 23, plus 4 fine sulcal processes. Range : diameter of 
central body 34-57[x, length of processes 8-31^. Number of specimens measured, 4. 



60 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. The smooth periphragm of the central body and processes is some- 
times slightly perforate but more commonly smooth. At the base of each process 
there is a characteristic thickening of the endophragm, which is here reticulate. 
Only four well preserved specimens have been observed, the number of wide 
tubular processes ranging from 22 to 24, with 1 to 6 fine sulcal processes. The 
antapical process is often distinctly wider than the other processes. The reflected 
tabulation appears to be comparable to H. tubiferum. 

H. simplicispinum sp. nov. is present throughout the Barremian of Yorkshire. 

Remarks. In general appearance H. simplicispinum strongly resembles Cordo- 
sphaeridium eoinodes but the fibrous periphragm is absent and the number of 
processes is greater. 

The reflected tabulation of H. simplicispinum is probably the same as H. tubiferum, 
but they differ in that the processes of the former are considerably more divided and 
not so expanded distally. 



Hystrichosphaeridium patulum sp. nov. 
PI. 10, fig. 5 

Derivation of name. Latin, patulus, broad and spreading — with reference of 
the larger processes. 

Diagnosis. Spherical to sub-spherical central body, not exceeding 2551 in dia- 
meter, possessing a smooth thin wall and bearing two types of processes. Both 
types of same length and considerably expanded distally, one type much wider than 
the other. Distal margin entire and undulating. Length of processes one-quarter 
to one-half of the diameter of central body. Apical archaeopyle present. 

Holotype. B.M.(N.H.) slide ¥.51739(1). 7 feet above base of London Clay ; 
Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 11-5 by i4-5[x, length of 
processes up to 5- 5{jl, number of processes 25. Range : diameter of central body 
Ii-I9[i, length of processes 4-9^. Number of specimens measured, 8. 

Description. This species is characterized by its broad open processes, approxi- 
mately 2[jl wide, and by the finer processes, up to ifx wide. The processes are tubi- 
form with considerably expanded distal extremities measuring up to j\i across. The 
number of processes can be up to 25. The apical archaeopyle has straight edges 
obviously reflecting plate boundaries. 

Remarks. The small size of this species and the two types of processes are charac- 
teristic. Its processes resemble shortened and sometimes widened processes of 
H. tubiferum, and the number present is also similar. Some relationship may per- 
haps be inferred between these two species. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 61 

Hystrichosphaeridium arborispinum sp. nov. 
PI. 9, figs. 5, 10 

Derivation of name. Latin, arbor, tree ; spinus, spine — with reference to the 
tree-like appearance of the processes. 

Diagnosis. Sub-spherical to ovoidal central body composed of thin endophragm 
and granular or reticulate periphragm. Processes, composed of periphragm, 
hollow, tubiform, usually simple, expanding distally and terminating with complica- 
ted secate margin. Apical archaeopyle commonly present. 

Holotype. B.M.(N.H.) slide ¥.51727(3). Speeton Clay, Shell West Heslerton 
Borehole No. 1, Yorkshire at 39 metres depth. Lower Cretaceous (Middle Barremian). 

Dimensions. Holotype : diameter of central body 39 by 39fx, length of processes 
io-i9(x. Range : diameter of central body 31-43^, length of processes 10-23^. 
Number of specimens measured, 4. 

Description. The distal extremities of the processes have a distinctive ragged 
appearance due to the irregular shape of the secae — some being irregularly lobate, 
others giving off spines laterally. Specimens with fibrous processes, and more 
rarely with fenestrate processes, have been observed. An apical archaeopyle 
commonly seems to be present, but its precise nature is difficult to determine for 
the specimens are extremely thin walled and easily distorted. The number of 
processes seems to be standardized at 22 to 23, and this together with their arrange- 
ment on the surface of the central body indicate that H. arborispinum sp. nov. has a 
reflected tabulation similar to that of H. tubiferum. 

This species has been recorded only from the Lower and Middle Barremian of 
Yorkshire. 

Remarks. The form of the distal extremities of the processes characterizes this 
species and distinguishes it from all other described species. 

H. arborispinum is basically of the same type as H. tubiferum (Lejeune-Carpentier 
1940) but has slightly broader processes which are distally much more divided. 

Hystrichosphaeridium salpingophorum (Deflandre) 
PI. 10, fig. 6 

1935. Hystrichosphaera salpingophora Deflandre : 232, pi. 9, fig. 1. 

1937. Hystrichosphaeridium salpingophorum (Deflandre) Deflandre : 80, pi. 13, figs. 1, 3. 

1940. Hystrichosphaeridium salpingophorum (Deflandre) ; Lejeune-Carpentier: 219, text-fig. 8. 

1947. Hystrichosphaeridium salpingophorum (Deflandre) ; Deflandre, text-fig. 1, no. 7. 

?i948. Hystrichosphaeridium salpingophorum (Deflandre) ; Pastiels : 37, pi. 3, figs. 3-7. 

?i952. Hystrichosphaeridium salpingophorum (Deflandre) ; W. Wetzel : 399, text-fig. 11. 

?I952. Hystrichosphaeridium salpingophorum (Deflandre) ; Gocht, pi. 1, fig. 19 ; pi. 2, fig. 20. 

1952. Hystrichosphaeridium salpingophorum (Deflandre) ; Deflandre, text-fig. 11. 

1955. Hystrichosphaeridium salpingophorum (Deflandre) ; Deflandre & Cookson : 271, pi. 2, 

fig- 9- 
?i958. Hystrichosphaeridium salpingophorum (Deflandre) ; Eisenack : 401, pi. 27, figs. 5, 6. 



62 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Emended diagnosis. Central body spherical to ovoidal with characteristic 
reflected tabulation of 4', 6", 6c, 5'", ip, 1"" with variable number of sulcal processes. 
Processes well developed, tubiform, with sub-quadrate distal openings. Distal 
margins entire or denticulate. Number of processess present 25 to 30. Apical 
tetratabular archaeopyle practically always present. 

Holotype. Slide AJ56, Laboratoire de Micropaleontologie, Ecole Pratique des 
Hautes Etudes, Paris. Senonian ; France. 

Material (Figured). B.M.(N.H.) slide ¥.51734(1). 146 feet above base of 
London Clay ; Whitecliff Bay, Isle of Wight. 

Dimensions. Range of specimens from type material (Deflandre 1937) ; dia- 
meter of central body 35 to 40[x, length of processes 25 to 30[x, the number of processes 
is approximately 30. Range of London Clay specimens : diameter of central body 
30-44^, length of processes 14-20^. Number of specimens measured, 4. 

Description. The surface of the central body may be smooth or slightly granular, 
and composed of two layers, the endophragm and periphragm (absent beneath the 
processes). The processes expand gradually towards the distal sub-quadrate 
opening, which is up to i8[i across in the London Clay forms. Medially the processes 
rarely exceed iOfj. and are usually much less. The wall of the processes (composed 
of periphragm) is slightly fibrous. The distal margin can be serrate, undulose or 
even aculeate. Processes may be perforate distally. 

Remarks. The London Clay specimens have rather short and broader processes 
than the holotype and are perhaps a variety of H. salpingophorum. The ribs, 
illustrated by Element (i960), extending along the length of the processes and run- 
ning into the central body have not been observed. The specimen figured by 
Lejeune-Carpentier (1940, text-fig. 8) is very similar to the London Clay forms. 

H. salpingophorum (London Clay) is generally easily distinguished from H. tubi- 
ferum. However certain specimens from the London Clay are transitional, often 
showing the circle formed at the junction of the processes and the endophragm. A 
close relationship with H. tubiferum is also indicated by the identical tabulation and 
intratabular processes. 

The Jurassic forms formerly attributed to H. salpingophorum are transferred 
below to Hystrichosphaeridium costatum sp. nov. 

Hystrichosphaeridium costatum sp. nov. 
PI. 10, fig. 4 

?i938. Hystrichophaeridium salpingophorum (Deflandre) ; Deflandre : 186, pi. 10, figs. 1-3. 

?i947. Hystrichosphaeridium salpingophorum (Deflandre) ; Deflandre, text-fig. 1, no. 6. 

?i952. Hystrichosphaeridium salpingophorum (Deflandre) ; Deflandre, text-fig. 10. 

i960. Hystrichosphaeridium salpingophorum (Deflandre) ; Klement : 55, pi. 7, figs. 3-5 ; 
text-fig. 31. 

i960. Hystrichosphaeridium salpingophorum (Deflandre) ; Sarjeant : pi. 13, fig. 7. 

1961. Hystrichosphaeridium salpingophorum (Deflandre) ; Sarjeant : 99, pi. 15, fig. 7. 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 63 

Derivation of name. Latin, costa, rib — referring to the thickenings of the 
periphragm. 

Diagnosis. Subspherical central body possessing a moderate number of fibrous 
tubiform processes having sub-quadrate distal openings. Distal margin denticulate 
with small number of recurved prolongations. Thickened ribs extending from some 
of the angles of the distal margins along length of processes and onto central body 
surface where they connect with similar ribs extending from neighbouring processes, 
forming mesh-like structure. Apical archaeopyle usually present. 

Holotype. B.M.(N.H.) slide V.51708, from G.R. 053890, Scarborough Castle, 
Yorkshire. Oxford Clay (Quenstedtoceras mariae Zone). 

Dimensions. Holotype : diameter of central body 47 by 47^, length of processes 
19-28(1, number of processes 24. 

Description. The surface (periphragm) of the central body is granular or 
slightly reticulate. The tubiform processes have broad bases, and splay out distally 
in an angular fashion, their width not exceeding c»jx medially. At the angles of the 
margin are commonly situated small prolongations or spines, occasionally up to 8jjl 
long but usually considerably smaller. The processes vary considerably in width, 
from 1 to o,fx when measured medially. Only one or two finer processes are present 
on a specimen and these are probably sulcal processes. An occasional deeply 
furcate process has been observed in the central region of the cyst, these undoubtedly 
being cingulum processes. The ribs (thickenings of the periphragm) are very 
characteristic and form upon the surface of the central body a subpolygonal mesh- 
like arrangement, somewhat simulating the tabulation seen in the genus Hystri- 
chosphaera, but certainly not analogous to it. An apical archaeopyle is usually 
present, and the reflected tabulation appears to be that typical for this genus. 
Hystrichosphaeridium costatum sp. nov. has been recorded from the Oxfordian of 
England, France and Germany. 

Remarks. Deflandre (1938) described H. salpingophorum from the Oxfordian 
noting the ribbed processes and an apparent similarity to the Upper Cretaceous form 
of this species. However, ribbing on the surface of the central body was not 
remarked on or shown in his illustrations (pi. io, figs. 1-3). These forms possibly 
belong to H. costatum. 

Klement (i960) described and figured specimens identical to those found in the 
British Oxfordian, possessing the characteristic thickenings of the periphragm. 

The specimen illustrated by Lejeune-Carpentier (1940, text-fig. 7) from the Upper 
Cretaceous, has vague polygonal markings on the surface of the central body, but 
definite ribs are absent. 

Sarjeant (i960, 1961) illustrated specimens of H. costatum as H. salpingophorum ; 
his figured specimen (1961, pi. 15, fig. 7) has been selected as holotype of the new 
species. 



64 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Hystrichosphaeridium readei sp. nov. 
PI. 6, fig. 3 

?I940. Hystrichosphaeridium salpingophorum (Deflandre) ; Lejeune-Carpentier : 219, text- 
fig- 7- 
?i940. Hystrichosphaeridium tubiferum (Ehrenberg) ; Lejeune-Carpentier : 218, text-fig. 5. 

Derivation of name. Named in honour of the Reverend J. B. Reade who was 
the first to describe and figure (1839) hystrichospheres from English flints of the 
Upper Cretaceous age. 

Diagnosis. Spherical to subspherical central body composed of smooth endo- 
phragm and periphragm. Processes, composed of the latter, slightly fibrous, 
cylindrical and open. Larger processes with two thickenings of periphragm extend- 
ing along their length over surface of central body and joining up with similar 
thickenings from neighbouring processes. Processes varying in width and expanding 
distally, terminating in fairly complicated aculeate or secate margin. Apical 
archaeopyle usually present. 

Holotype. Geol. Surv. Colin, slide PF.303o(2). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 690 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 41 by 45[x, length of processes 
23-2951., number of processes 24. Range : diameter of central body 3i-54fi., length 
of processes 20-35^. Number of specimens measured, 8. 

Description. The most characteristic feature of this species is the presence of 
thickenings or ribs in the periphragm. These ribs are close together near the distal 
end of the process and gradually diverge proximally, before separating completely 
on the surface of the central body, each rib passing to a different neigbouring process. 
Thus triangular and polygonal networks are seen on the surface of the central body. 
The sulcal processes are usually noticeably finer than the others and are very occa- 
sionally joined by septa, as seen in the holotype. The septa are probably modified 
ribs. An apical archaeopyle is usually present. The number of processes in the 
specimens observed varied between 23 and 27. The reflected tabulation is difficult 
to determine but it is probably comparable to H. tubiferum i.e. 4', 6", 6c, 5'", ip, 
1"" and xs. 

H. readei sp. nov. occurs in the Upper Cenomanian at Fetcham Mill, Surrey and 
has not been recorded lower in the succession at this locality. 

Remarks. The Cenomanian species strongly resembles and is undoubtedly 
related to, H. costatum from the Upper Jurassic. The only apparent difference 
between the species is in the extremities of the processes. In H. costatum the 
extremities are simply denticulate with a small number of spines, whereas in H. 
readei the extremities are considerably more complex. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 65 

H. tubiferum (Ehrenberg) as illustrated by Lejeune-Carpentier (1940, text-fig. 5), 
from Upper Cretaceous flint, is extremely similar to H. readei and could well belong 
to the present species. 



Hystrichosphaeridium radiculatum sp. nov. 

PI. 7, fig. 8 ; PL 9, fig. 6 

Derivation of name. Latin, radicula, small root — with reference to the fibres 
radiating from the bases of the processes. 

Diagnosis. Spherical to sub-spherical central body composed of reticulate 
endophragm and fibrous periphragm. Processes, approximately 30 in number, 
composed of periphragm, fibrous, mainly hollow and open distally, simple tubiform 
or dividing into 2 or 3 sub-parallel branches. Processes expanding slightly distally, 
extremities of processes entire or denticulate. 

Holotype. Geol. Surv. Coll. slide PF.303i(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 690 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 36 by 37^, length of processes 
I3-I7[x. Range : diameter of central body 3i-37[x, length of processes n-17^. 
Number of specimens measured, 4. 

Description. The reticulate endophragm appears to be granular at first sight 
before examination in detail. Along the lengths of the processes run fibrous strands 
which continue on to the surface of the central body and are sometimes continuous 
with similar strands from neighbouring processes. The depth of the furcation of the 
processes varies considerably, from merely a slight distal furcation to where there 
appears to be two separate processes in close proximity. A rather elongate apical 
archaeopyle is present surrounded by 6 precingular processes. The distribution of 
the remainder of the processes is difficult to determine precisely. 

This species is uncommon and has only been identified from the Upper Cenomanian. 

Remarks. H. radiculatum sp. nov. is closely related to H. mantelli differing in that 
the branched processes are more common and the fibrils of the processes continue 
across the surface of the central body. The reflected tabulation of the two species is 
probably very similar. 

Hystrichosphaeridium cf. clavigerum (Deflandre) as illustrated by Lejeune-Carpen- 
tier (1940, text-fig. 9), resembles H. radiculatum in size, form of the processes, and the 
fibrous periphragm on the surface of the central body. However, the branching 
processes characteristic of H. radiculatum, are absent. 



66 MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 

Hystrichosphaeridium mantelli sp. nov. 
PI. 6, fig. 6 

Derivation of name. In honour of the geologist and microscopist Gideon 
Algernon Mantell, who did much pioneer work in interpreting the structure of 
Upper Cretaceous microplankton during the mid-nineteenth century. 

Diagnosis. Spherical to sub-spherical central body composed of thin endo- 
phragm and granular or finely reticulate periphragm. Periphragm of processes 
slightly fibrous. Processes predominantly simple, tubiform, buccinate or bulbose, 
open distally with digitate or foliate margin. Occasionally narrow, solid, closed 
processes occur. Number of processes 26 or less, one process per plate area. Apical 
archaeopyle usually present. 

Holotype. Geol. Surv. Colin, slide PF. 3032(1). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 41 by 42^, length of processes 
13-2 1 [i, number of processes 25. Range : diameter of central body 36-45^, length 
of processes i3-26[x. Number of specimens measured, 6. 

Description. At first sight the periphragm of the central body appears to be 
fairly heavily granular, but on closer examination the granules apparently result 
from a fine reticulation. The processes are erect and extremely variable in form, 
being tubiform, buccinate or even bulbose, usually open but occasionally closed, and 
simple or branched distally. The closed processes are extremely narrow, less than 
ipi, and solid distally. An apical archaeopyle appears always to be present. The 
processes give a reflected tabulation of 6", 6c, 5'", ip, 1"" and a variable number of 
sulcal processes, commonly 4-6. The detached apical region has not yet been 
identified. 

This species has been found only in the Lower Cenomanian and is extremely 
uncommon. 

Remarks. The reticulate nature of the central body and the fibrous processes 
differentiate H. mantelli sp. nov. from most other species. H. radiculatum sp. nov. is, 
however, fairly similar but the processes are more deeply divided, there often being 
2 to 3 sub-parallel branches, and narrower. 

Hystrichosphaeridium latirictum sp. nov. 
PI. 10, fig. 8 

Derivation of name. Latin, lati, wide and rictum, open mouth — with reference 
to the considerably expanded distal margins of the processes. 

Diagnosis. Central body ellipsoidal, with smooth or slightly granular wall up to 
one-quarter \l thick. Processes slender, tubiform, slightly fibrous, expanding 
considerably distally. Processes open distally and margin circular or quadrate. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 67 

Holotype. B.M.(N.H.) slide ¥.51740(1). Metropolitan Water Board Borehole 
No. 11 at 43-25 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 18 by 19-5^, length of proces- 
ses 9-12- 5[i., breadth of processes up to 2jx, length of acuminate processes 6-8[x, 
number of processes 25 (and two acuminate processes) . Range : diameter of central 
body n-20[x, length of processes 6-i^\i. Number of specimens measured, 5. 

Description. The processes show a variation in outline and nature of distal 
margin which can be circularly to ovoidal, serrate, undulose or aculeate. The 
distal extremities of the processes are usually considerably expanded, up to I3(x wide. 
The length of the processes vary from one-third to two-thirds of the diameter of the 
central body. Besides the tubiform process there is quite often a small number of 
short, closed processes, as on the holotype. The latter are undoubtedly sulcal 
processes. An apical archaeopyle is present surrounded by 6 processes, the reflected 
tabulation probably being that of this genus. 

H. latirictum sp. nov. has been recorded from the London Clay of Enborne and of 
Whitecliff Bay, Isle of Wight. 

Remarks. The size of H. latirictum sp. nov., in combination with the tubiform 
processes, is quite characteristic. Polysphaeridium paulinae from the Middle 
Jurassic of France (Valensi 1953) is similar in form but smaller with more processes, 
the processes being not greater than one-third of the diameter of the central body. 
It is possible that this species may result from misinterpretation of representatives 
of the genus Stephanelytron : the holotype, kindly lent by Prof. Deflandre for 
examination (in 1962), is at depth in flint and cannot be seen in full detail. Hystri- 
chospheres with tubular processes are not otherwise known from the Middle Jurassic. 



1839 
1842 
1844 
1848 
1851 

?I934 
1935 
1937 

?i940 

?I955 

?ig63 

1964 



Hystrichosphaeridium recur vatutn (White) 

Xanthidium tubiferum (Ehr.) : Reade, pi. 9. figs. 6, 9. 

Xanthidium tubiferum palmatum White : 39, pi. 4, div. 3, fig. 12. 

Xanthidium tubiferum palmatum White ; White, pi. 8, fig. 11. 

Xanthidium palmatum White ; Bronn : 1375. 

Spiniferites palmatus (White) Mantell : 251, text-fig. 79. 

Hystrichosphaera tubifera (Ehr.) ; Deflandre, text-fig. 11. 

Hystrichosphaera tubifera (Ehr.) ; Deflandre : 15, pi. 7, fig. 10, ?n. 

Hystrichosphaeridium tubiferum (Ehr.) ; Deflandre : 96, pi. 13, fig. 2 ; (pi. 12, fig. 14 ; 

pi. 13. fig- 4)- 
Hystrichosphaeridium recurvatum (White) Lejeune-Carpentier : 221, text-fig. 6. 
Hystrichosphaeridium tubiferum (Ehr.) ; Valensi : 592, pi. 4, fig. 2 ; pi. 5, fig. 8. 
Hystrichosphaeridium recurvatum (White) ; Gorka : 57, pi. 8, fig. 8 ; text-pl. 6, fig. 5. 
Hystrichosphaeridium recurvatum (White) ; Sarjeant : 173. 



Emended diagnosis. Sub-spherical central body with moderate number of 
slender tubiform processes. Length of latter between that of radius and diameter of 
central body. Processes open distally, terminating with a few short orthogonal or 
recurved spines. 



c.s MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Neotype. Slide AJ97, Laboratoire de Micropaleontologie, Ecole Pratique des 
Hautes Etudes, Paris. (Figured by Deflandre 1935, pi. 7, fig. 10.) Senonian flint 
from the Paris Basin. 

Dimensions. Holotype (measured from the illustration) : diameter of central 
body 32 by 25^, maximum overall diameter 75^, length of processes 18-30^, number 
of processes, 25. 

Description. The periphragm of the central body is smooth or slightly granular 
and of the processes is smoother or somewhat fibrous. The processes on a specimen 
do not vary a great deal in their length or width, the sulcal processes not being 
significantly smaller. Each process has constant width along its length, widening 
slightly at the base but not distally, where it terminates in a rosette of short spines. 
An apical archaeopyle is usually present. The reflected tabulation appears to be 4', 
6", 6c, 5'", ip, 1"" and 3-6S, and so H. recurvatum is provisionally placed in the 
genus Hystrichosphaeridium. 

H. recurvatum has only been recorded with certainty from the Senonian of Europe. 

Remarks. Sarjeant (1964a), in a paper on nomenclatural problems, pointed out 
that on the principle of priority the correct name for this species is H. palmatum and 
not H. recurvatum. White (1842) referred to this species in the text as Xanthidium 
recurvatum or palmaforme and in the plate caption as X. palmatum. Thus three 
alternative names were suggested. Bronn (1848) was next to refer to this species, 
and listed it as X. palmatum. In 1939 a junior homonym to the latter was proposed 
by Deflandre & Courteville, this later being transferred to the genus Baltisphaeridium 
(Downie & Sarjeant 1963). 

Lejeune-Carpentier (1940), overlooking the work of Bronn, described this species 
under the name of H. recurvatum. Subsequent workers have followed Lejeune- 
Carpentier and used H. recurvatum as the specific name instead of the correct 
H. palmatum. Downie & Sarjeant (1964) similarly use H. recurvatum. Since the 
latter is in general use and H. palmatum (White) Bronn has a junior homonym, it is 
proposed that H. recurvatum should be retained as the designation for this species. 

A thorough search has been made to find the holotype of H. recurvatum from the 
British Senonian, figured by White (1842), but without success. It has therefore 
been necessary to propose a neotype for this species. The neotype proposed was 
first figured by Deflandre (1935, pi. 7, fig. 10) as Hystrichosphaera tubifera and comes 
from the Senonian of France (Paris Basin). 

Hystrichosphaeridium sheppeyense sp. nov. 
PI. n, fig. 3 

1955. Hystrichosphaeridium recurvatum (White) ; Deflandre & Cookson : 269, pi. i. fig. 11. 
1961. Hystrichosphaeridium recurvatum (White) ; Evitt : 391, 395, pi. 4, figs. 3-5 ; pi. 5, 
fig. 8. 

Derivation of name. Named after the type locality, the Isle of Sheppey, Kent. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 69 

Diagnosis. Ovoidal central body with smooth or slightly granular surface. 
Processes tubular, open distally, approximately equal in length to radius of central 
body, terminating in a number of orthogonal or recurved spines. 

Holotype. B.M.(N.H.) slide ¥.51741(1). 85 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : overall diameter 59 by 57^, diameter of central body 
29 by 31 [x, length of processes i4-i8[z, width of processes up to 2\i, number of 
processes 26. 

Description. The processes are relatively thick walled, the tubule being narrow 
and sometimes constricted. At the bases of some of the processes there are small 
proximal elevations or swellings. Distally the processes splay out into 2 to 7 
spines or secae, up to 6jx long. An apical archaeopyle is usually present. The 
tabulation reflected by the processes is that of Hystrichosphaeridium. 

Remarks. H. sheppeyense sp. nov. differs from H . recurvatum (White) in being 
considerably smaller and possessing relatively short processes. The forms described 
and figured by Deflandre & Cookson (1955) and by Evit (1961) are identical in all 
respects except that the former, from the Senonian, is rather larger. Deflandre & 
Cookson's figured specimen has an overall diameter of 90^, central body diameter of 
44 by 51^ and processes 16-26(1 in length. 

Hystrichosphaeridium bowerbanki sp. nov. 
PL 8, figs. 1, 4 

Derivation of name. After J. S. Bowerbank who was one of the first British 
microscopists to record hystrichospheres from the Chalk, and the first to record them 
from the Upper Greensand. 

Diagnosis. Ovoidal to elongate central body with smooth surface. Processes 
thin-walled, tubular, open distally, sometimes widening considerably at their base, 
and greater than half the central body diameter in length. They terminate in a 
number of orthogonal or recurved spines. Apical archaeopyle usually present. 

Holotype. Geol. Surv. Colin, slide PF. 3033(1). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey at 730 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : overall diameter 85 by j8y., diameter of central body 
39 by 29[x, length of processes 24-26(1, number of processes 24. Range : overall 
diameter 60-85(1, diameter of central body 29-40(0., length of processes 21-26. 
Number of specimens measured, 5. 

Description. The central body is characteristically ovoidal to elongate. The 
tubular processes are thin- walled and usually curved or bent to some extent. The 
distal spines are 5 to 7 in number and are up to 6fx in length. The processes are 
cylindrical for most of their length, 2-5 to 3^ wide and expand slightly distally to 
about 4[x before giving rise to spines. Proximally the processes sometimes widen 



70 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

considerably and may measure up to iOfj. at their contact with the central body and 
often show noticeable basal wrinkles. An apical archaeopyle always appears to be 
present. The tabulation reflected by the processes is : (4'), 6", 6c, 5'", ip, 1"" and 
about 5s. 

Remarks. H. bowerbanki sp. nov. differs from H. recurvatum (White) in being 
smaller and having wider tubular processes. It is rather similar to H. sheppeyense 
but the form of the central body is more elongate ; the processes are wider, especially 
at their base, and have a much thinner wall. 



OTHER SPECIES 

The following species are here attributed to the genus Hystrichosphaeridium 
emend, on the basis of the number of processes and general form : 

Hystrichosphaeridium cf. clavigerum (Deflandre) ; Lejeune-Carpentier 1940. 
Upper Cretaceous ; Belgium. 

Hystrichosphaeridium irregulare (Merrill 1895). Lower Cretaceous ; U.S.A. 

Hystrichosphaeridium stellatum (Maier 1959). Oligocene ; Germany. 

The following described species are doubtfully included in Hystrichosphaeridium 
emend, on the basis of the number and form of processes present : 

? Hystrichosphaeridium arundum (Eisenack & Cookson i960). Upper Cretaceous ; 
Australia. 

? Hystrichosphaeridium aquitanicum (Deunff 1961). Lower-Upper Cretaceous ; 
France. 

? Hystrichosphaeridium gliwicense (Macko 1957). Miocene ; Poland. 

? 'Hystrichosphaeridium hilli (Merrill 1895). Lower Cretaceous ; U.S.A. 

? Hystrichosphaeridium polyplasium (Maier 1959). Miocene ; Germany. 

Hystrichosphaeridium claviferum (Wilkinson 1849) '> Deflandre 1946a (incorrectly 
transferred to Baltisphaeridium by Downie & Sarjeant 1963) and Hystrichosphaeri- 
cruciatum O. Wetzel 1933 from the description and figures both appear to be the 
detached apical regions of species of Hystrichosphaeridium emend., bearing four 
processes. The holotype of H. clavigerum is lost ; it appears likely that it represents 
the apical region of H. tubiferum, of which the species H. clavigerum may be regarded as 
a junior synonym and should therefore be rejected. H. cruciatum, as illustrated 
by Lejeune-Carpentier (1940, fig. 14), represents the apical region of an otherwise 
undescribed species. 



Genus OLIGOSPHAERIDIUM nov. 

Derivation of name. Greek, oligo, few or scanty ; sphaera, ball — with reference 
to the ball-like central body bearing a small number of processes. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 71 

Diagnosis. Subspherical chorate cysts possessing a reflected tabulation of 4', 
6", 5-6'", ip, 1"". Processes tubiform, open distally, intratabular, one process per 
plate area. Number of processes never more than 18. Archaeopyle apical. 

Type species. Xanthidium tubiferum complex White 1842. Upper Cretaceous ; 
England. 

Remarks. Cingular processes are absent, there commonly being 6 postcingular 
processes. The processes are approximately of equal length on an individual but 
are variable within a species. They are always open and can be cylindrical to 
infundibular with perforate or entire walls. Endophragm confined to the central 
body, surrounded by periphragm which alone forms the processes. Processes never 
in contact with the interior of the central body. 

An alternative formula for the reflected tabulation is : 4', 6", 5'", ip, 1"" and 
o-is. In the specimens possessing 14 processes, all are of the same size and one 
would expect if one sulcal process was present that this would be smaller than the 
other processes. This corresponds to the typical Gonyaw/ax-tabulation in which 
there are 6 postcingular plates, plate 1'" sometimes being considerably reduced. 
The original tabulation is tentatively reconstructed in Text-fig. 1. 

Oligosphaeridium complex (White) 
PL 7, figs. 1, 2 ; PI. 10, fig. 3 ; Text-fig. 14 

Xanthidium tubiferum complex White : 39, pi. 4, div. 3, fig. 11. 

Xanthidium tubiferum complex White ; White : pi. 8, fig. 10 ; text-figs. 

Xanthidium complexum (White) Bronn : 1375. 

Hystrichosphaeridium elegentulum Lejeune-Carpentier : 22, text-figs. 11, 12. 

Hystrichosphaeridium complex (White) Deflandre : 11. 

Hystrichosphaeridium complex (White) ; Firtion : 156, pi. 9, figs. 2, 4, 5 ; text-fig. 

iA-F. 
Hystrichosphaeridium complex (White) ; Deflandre & Cookson : 270, pi. 1, figs. 9, 10. 
Hystrichosphaeridium complex (White) ; Valensi : 592, pi. 4, fig. 3. 
Hystrichosphaeridium complex (White) ; Cookson & Eisenack : 42, pi. 12, fig. 10. 
Hystrichosphaeridium complex (White) ; Eisenack : 400 pi. 26, 400, figs. 3-5 ; pi. 25, 

fig. 16? 



1842 
1844 
1848 
1940 
1946 
1952 

1955 

1955 

?i 9 58 

1958 

1959 
?I962 
?ig63 

1964 



Hystrichosphaeridium complex (White) 
Hystrichosphaeridium tubiferum (Ehr.) 
Hystrichosphaeridium tubiferum (Ehr.) 
Hystrichosphaeridium complex (White) 



Gocht : 66, pi. 3, figs. 2, 3 ; pi. 7, figs. 5, 6. 
Pocock : 83, pi. 15. fig. 230. 
Baltes, pi. 2, figs. 1-3, 5, 6. 
Cookson & Hughes : 46, pi. 9, fig. 6. 



Emended diagnosis. Central body sub-spherical to ovoidal. Wall composed of 
thin endophragm and periphragm, the latter giving rise to processes. Processes 
simple or branched, cylindrical for most of their length, open and expanded distally 
with aculeate or secate margin. Reflected tabulation inferred 4', 6", 5-6'", ip, 1"". 
Apical archaeopyle usually present having zig-zag margin. Processes in complete 
specimen not exceeding 18. 

Neotype. Geol. Surv. Colin, slide PF.3034(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 750 feet depth. Upper Cretaceous 
(Cenomanian). 



72 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Neotype : diameter of central body 35 by 35^., length of processes 
22-25^. Range : diameter of central body 34-55^, length of processes 22-4310.. 
Number of specimens measured, 9. 

Description. In the specimens from the Cenomanian, the periphragm of the 
central body is smooth or very slightly granular. The processes are cylindrical for 
most of their length, with an expanded opening distally, the margin of which is 
developed into aculei and secae. The aculei and secae can be simple or branched, 
erect or patulate, orthogonal or even recurved. Where the processes meet the central 
body there is often a clearly marked ring indicating the point of divergence of the 
endophragm and periphragm. The wall of the processes is smooth or faintly 
fibrous ; their length usually measures between the radius and the diameter of the 
central body. 

The small number of processes and the apical archaeopyle, when present, enable 
one readily to determine the tabulation of 0. complex as reflected by the position of 
the processes. 

Specimens of 0. complex have been examined from two other horizons. 

Examples from the Speeton Clay (Barremian) of Yorkshire are very similar to 
the forms illustrated by Eisenack (1958). The periphragm of the central body is 
often slightly granular and some of the processes are more deeply divided and show 
more variation than is usual in this species. 11 specimens were measured, the 
diameter of the central body being 35-62(1 and the length of the processes 13-471X. 

Specimens from the London Clay (Ypresian) strongly resemble the Cenomanian 
forms, the processes perhaps being a little stouter. Diameter of central body 
2g-$8\i, length of processes 23-39^ (6 specimens measured) . 




Fig. 14. Oligosphaeridium complex (White). A specimen from the Cenomanian, in lateral 
view, showing the angular apical archaeopyle and the distribution of the processes. 
X c. 420. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 73 

0. complex thus has a stratigraphic range from the Neocomian (Gocht 1959 and 
Cookson & Eisenack 1958) to the Ypresian. 

Remarks. Oligosphaeridium complex was first described by White (1842) as 
Xanthidium tubiferum complex. In the description of the processes White stated : 
" Sometimes the orifice is separated into unequal divisions of four, five and six parts, 
in others like one variety of X. ramosum before noticed ; the branching terminations 
are of a more complex structure, each branch having at its extremes a further 
ramification ; at which last I am inclined not to consider a variety of one species, 
but the same as the former, in an advanced state of development. " Lejeune- 
Carpentier (1940) briefly described forms having distal prolongations under Hystri- 
chosphaeridium elegantulum. These she compared to X. tubiferum complex (White) 
and concluded that they were identical. In White's figures branching is clearly 
shown ; Lejeune-Carpentier's figures 11 and 12, however, suggest that some at 
least of the so-called distal branchings of the processes are bifurcating secae of simple 
processes. H. elegantulum was transferred to H. complex by Deflandre (1946) on the 
grounds that it was an invalid synonym, but no new diagnosis was given for H. 
complex. Firtion (1952) figured different process terminations for the species. 
These cannot be seen in his indistinct plates and in his description he simply states 
" . . . . the shell is furnished with tubiform radiating appendages ; their distal 
extremity very splayed-out, showing a system of fine and deep dentations." 

H. tubiferum (Cookson 1953, pi. 2, fig. 24) later placed in H. complex (Deflandre & 
Cookson 1955) is of doubtful status. 

Valensi (1955) figured H. complex, branching in at least four processes. In the 
same year, Deflandre & Cookson enlarged the concept of this species by including 
within it specimens having cathrate extremities, transitional to H. pulcherrimum. 
Their figures closely approach the London Clay forms. Cookson & Eisenack (1958) 
figured H. complex with simple processes developed distally into aculei. Eisenack 
(1958) Gocht (1959) and Cookson & Hughes (1964) figured specimens with simple 
unbranched processes, produced distally into aculei. 

Neale & Sarjeant (1962) in discussing their new species H. macrotubulum decided 
that forms possessing unbranched processes did not belong to H. complex. Partly 
on this basis, partly on the granular nature of the central body, they separated 
H. macrotubulum as a distinct species. In view of the uncertainty concerning the 
degree of branching of the processes, both branched and simple forms have been 
included in H. complex. 

Much more significant is the tabulation inferred from the positions of the processes. 
The specimens of H. complex illustrated by Firtion (1952), Deflandre & Cookson 
(1955), Cookson & Eisenack (1958) and Gocht (1959) are clearly forms lacking 
cingulum processes and possessing an apical archaeopyle. 

As Deflandre & Cookson (1955) noted, transitional forms to H. pulcherrimum 
occur, which have perforate processes ; the perforations are not, however, excessively 
numerous and for this reason the specimens concerned were placed in H. complex. 
Comparable forms have been observed in the Cenomanian of England. 



74 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

The specimens attributed to H. complex by Baltes (1963, pi. 3, figs. 1-3) do not 
belong in this species. In contrast, the forms he illustrates as H. tubiferum (pi. 2, 
figs. 1-3, 5, 6) undoubtedly belong to Oligosphaeridium and probably to 0. complex. 

The holotype of 0. complex from the British Senonian illustrated by White 
(1842, pi. 4, div. 3, fig. 11) cannot be traced. A neotype has therefore been chosen 
from the Cenomanian of Surrey (England). 

Oligosphaeridium reticulatum sp. nov. 
PL 7, fig. 10 

Derivation of name. Latin, reticulatus, net-like — with reference to the reticulate 
or net-like appearance of the surface of the central body. 

Diagnosis. Subspherical central body composed of reticulate endophragm. 
Periphragm confined to processes, smooth or slightly fibrous. Processes simple, 
cylindrical, expanding distally and terminating in complicated aculeate or secate 
margin. Archaeopyle apical. Number of processes in complete specimen never 
exceeding 18. Inferred tabulation 4', 6", 5'", ip, 1"" and o-is. 

Holotype. Geol. Surv. Colin, slide PF. 3035(1). Lower Chalk, Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 29 by 30^, length of processes 
15-26^, number of processes 14. Range : diameter of central body 29-47^, 
length of processes 14-26(1. Number of specimens measured, 5. 

Description. The reticulate endophragm appears to be granular at low magni- 
fication, but at high magnification it is clearly seen to be finely reticulate. The 
cylindrical processes expand slightly proximally, forming a characteristic circle 
or oval on the surface of the central body. Distally they expand in the form of an 
open funnel often having an extremely ragged margin. 

Remarks. 0. reticulatum sp. nov. is very similar to 0. complex, differing only in 
the reticulate nature of the central body and the relative shortness of the processes. 
It is very significant that the inferred tabulations are identical, indicating a close 
phylogenetic relationship. 

Oligosphaeridium vasiformum (Neale & Sarjeant) 
PL 9, fig 7 ; PL 10, fig. 1 ; Text-fig. 1 

1962. Hystrichosphaeridium vasiformum Neale & Sarjeant : 452, pi. 20, fig. 1 ; text-fig. 8b. 
1965. Hystrichosphaeridium vasiformum Neale & Sarjeant ; Sarjeant, text-fig. 3C. 

Emended diagnosis. Sub-spherical to sub-quadrate central body composed of 
thin, smooth endophragm and thicker pitted periphragm. Not more than 18 
processes present, composed of smooth periphragm. Processes simple, tubiform and 
expanding distally, distal margin bearing few spines. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 75 

Holotype. B.M.(N.H.) slide ¥.51709(1). Speeton Clay, Shell West Heslerton 
Borehole No. 1, Yorkshire, at 99-25 metres depth. Lower Cretaceous (Middle 
Hauterivian) . 

Dimensions. Holotype : overall length 107- 5[x, breadth n6fx, central body 
length 46-5[x (apical region lacking), breadth 52^. 

Paratype. B.M.(N.H.) slide ¥.51709(3) : overall length 124-5^ breadth n6pi, 
central body length 46-5[i (apical region lacking), breadth 46-5^1. Range ; overall 
lengths 107-5-130^. (7 specimens). 

Description. The periphragm on the surface of the central body is moderately 
thick and pitted to a varying extent. The pits, passing through the periphragm and 
exposing the endophragm, vary greatly in size, being as much as ly. across. The 
processes arise from root-like bases and terminate distally in 4-6 simple spines. 
The processes do not connect with the interior of the central body. Rarely the 
processes possess small, often rectangular, areas where the periphragm is extremely 
thin, formerly described as perforations of the processes. 

An apical archaeopyle is usually present, the resulting specimens possessing 14 
processes. The inferred reflected tabulation is typical of the genus. 

The species has only been recorded from the Middle Hauterivian. 

Remarks. 0. vasiformum is very similar to 0. complex from the Barremian and is 
clearly related to it. The most important distinguishing features is the presence of 
the pitted periphragm on the surface of the central body in 0. vasiformum. The 
original tabulation of this species is tentatively reconstructed in Text-fig. 1. 

0. reticulatum sp. nov. is another related form, but its processes are usually 
noticeably shorter and stouter with a much more complex distal margin. 

Oligosphaeridium macrotubulum (Neale & Sarjeant) 
PI. 9, fig. 4 

1962. Hystvichosphaeridium macrotubulum Neale & Sarjeant : 452, pi. 20, fig. 7 ; text-fig. 8a. 

Remarks. A re-examination of the holotype has shown that the periphragm of 
the central body is pitted in exactly the same manner as in 0. vasiformum, albeit to 
a lesser extent. The processes have basically the same structure as in the latter 
species, but are perhaps slightly stouter than is typical. The holotype does not 
possess an archaeopyle, there being 18 processes present, indicating the reflected 
tabulation typical of this genus. As only the holotype of 0. macrotubulum was 
examined the range of variation cannot be ascertained, but it is probable that this 
species is synonymous with 0. vasiformum. 

Oligosphaeridium pulcherrimum (Deflandre & Cookson) 
PI. 10, fig. 9 ; PI. 11, fig. 5 

1955. Hystvichosphaeridium pulcherrimum Deflandre & Cookson : 270, pi. 1, fig. 8 text-figs, 21, 

22. 
1955. Hystvichosphaeridium pulcherrimum Deflandre & Cookson ; Valensi : 592, pi. 4, fig. 1. 



76 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Material (figured). B.M.(N.H.) slide ¥.51742(1). Metropolitan Water Board 
Borehole No. 11 at 63 feet depth, London Clay ; Enborne, Berkshire. 

Remarks. The processes of the London Clay specimens indicate a reflected 
tabulation of 4', 6", 6'", ip, 1"". The apical processes are relatively small and an 
apical archaeopyle is usually present. The fenestrate appearance of the processes in 
this species are extremely distinctive. The London Clay forms may be derived. 

Dimensions. London Clay forms : diameter of central body 30-48^, length of 
processes 17-40(1. Number of specimens measured, 3. 



Oligosphaeridium prolixispinosum sp. nov. 
PL 8, figs. 2, 3 

Derivation of name. Latin, prolixus, stretched out long and spina, thorny — 
with reference to the filiform spines at the distal extremities of the processes. 

Diagnosis. Elongate central body bearing few open tubular processes. Proces- 
ses terminating distally in a number of long thread-like spines. 

Holotype. Geol. Surv. Colin, slide PF.3036(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : overall width 64jx, diameter of central body 40 by 20\i, 
length of processes i8-24[x, number of processes 17. Range : Length of central body, 
33-43[x, width 20-2gjx, length of processes i8-29[x. Number of specimens measured, 

8. 

Description. The periphragm of the central body and of the processes is smooth. 
The processes are thin- walled and have a fairly broad base up to 8[i, with character- 
istic basal wrinkles. There are noticeable circles beneath the processes where only 
endophragm is present. The processes are about 3[A in width for most of their 
length tapering to 2(jl distally before giving rise to the filiform spines. The spines are 
extremely delicate, 5 to 8 in number, and up to I5[x in length. The number of 
processes varies from 16 to 18, the variation probably due to the number of sulcal 
processes present. In all specimens there is an obvious apical archaeopyle. Sur- 
rounding the archaeopyle are 6 precingular processes, then a diastema before the 
postcingular processes are reached. This diastema marks the position of the 
cingulum. The processes on the hypotract are difficult to assign to any dinoflagellate 
tabulation. There is no obvious antapical process, in fact 3 antapical processes 
usually seem to be present. The reflected tabulation appears to be (4'), 6", 6'", 
3"" and 1-3S. 

0. prolixispinosum sp. nov. is a rare species occurring throughout the Cenomanian 
of Surrey. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 77 

Remarks. 0. prolixispinosum sp. nov. is easily distinguishable from other species 
by its elongate form and small number of processes with very characteristic distal 
terminations. It should be noted that the basal wrinkles recorded in this species 
have also been seen in Hystrichosphaeridium bowerbanki. 

At the base of the Cenomanian there have been found, together with normal 
examples of 0. prolixispinosum, two specimens, which possess exactly the same 
elongate central body and type of processes but there are present 22 and 25 processes. 
This unusual number is caused by the presence of 6 cingular processes. It would thus 
appear that 0. prolixispinosum is, in the Lower Cenomanian, rather an unstable 
species and not until later in the Cenomanian does it settle down, the cingular 
processes being absent. 

Because of the above variation this species is rather difficult to classify since 
although the cingular processes are absent, it seems to be related to, or maybe even 
evolved from, a type possessing these processes. Two other factors are that the 
processes strongly resemble those found in H. bowerbanki and there may be 3 antapi- 
cal processes present although this is uncertain. Until further information is avail- 
able this species has been tentatively placed in the genus Oligosphaeridium because of 
the absence of cingular processes. 



OTHER SPECIES 

The following species are here attributed to the genus Oligosphaeridium on the basis 
of the number of processes and general form : 

Oligosphaeridium albertense (Pocock 1962). Lower Cretaceous ; Canada. 

Oligosphaeridium anthophorum (Cookson & Eisenack 1958). Upper Jurassic ; 
Australia and Papua. 

Oligosphaeridium perforatum (Gocht 1959). Lower Cretaceous ; Germany. 

Oligosphaeridium reniforme (Tasch, McClure & Oftedahl 1964). Lower Creta- 
ceous ; U.S.A. 

The following described species are doubtfully included in Oligosphaeridium on the 
basis of the number and form of the processes: 

? Oligosphaeridium asterigerum (Gocht 1959). Lower Cretaceous ; Germany. 

? Oligosphaeridium coelenteratum (Tasch, McClure & Oftedahl 1964). Lower 
Cretaceous ; U.S.A. 

~>. Oligosphaeridium dictyophorum (Cookson & Eisenack 1958). Upper Jurassic ; 
Papua. 

? Oligosphaeridium dispare (Tasch, McClure & Oftedahl 1964). Lower Cretaceous ; 
U.S.A. 

1 Oligosphaeridium irregular e (Pocock 1963 ; non Merrill 1895). Lower Cretaceous ; 
Canada. 

1 Oligosphaeridium par adoxum (Brosius 1963). Oligocene ; Germany. 



78 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Genus PERISSEIASPHAERIDIUM nov. 

Derivation of name. Greek, perisseia, abundance or surplus ; sphaera, 
ball— with reference to the rather superfluous sulcal and cingular processes. 

Diagnosis. Chorate cysts with sub-spherical central body composed of two 
membranes. Processes of two types : (i) larger, tubiform, open distally and 
intratabular ; one process per plate area, and (ii) smaller, closed processes restricted 
to sulcal and cingular regions. Tabulation reflected by tubiform processes 4', 6", 
5'", ip, 1"". Archaeopyle apical. 

Type species. Perisseiasphaeridium pannosum sp. nov. 

Remarks. This genus appears to be intermediate between Hystrichosphaeridium 
and Oligosphaeridium. It resembles the former in possessing both cingular and 
sulcal processes, but these are closed, and the latter since the tabular processes 
reflect a similar tabulation. It resembles Hystrichokolpoma in the presence of both 
tabular and closed processes, but the former are of a completely different type, 
being conical and covering most of the plate area. Also only 4 tabular postcingular 
processes are present in the genus Hystrichokolpoma whereas 5 are present in Peris- 
seiasphaeridium. 

Perisseiasphaeridium pannosum sp. nov. 
PL 3, fig. 5 ; PI. n, fig. 8 : Text-fig. 15 

Derivation of name. Latin, pannosus ragged — with reference to the ragged or 
torn appearance of the infundibular processes. 




Fig. 15. Perisseiasphaeridium pannosum sp. nov. A specimen from the London Clay, 
ventral view, showing the distribution of the processes. x c. 1000. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 79 

Diagnosis. Chorate, sub-spherical to ovoidal cyst bearing two types of processes. 
One with broad open infundibular processes, often fenestrate distally ; the other 
with smaller slender processes, closed, with simple or bifurcate extremities. Apical 
archaeopyle present. 

Holotype. B.M.(N.H.) slide ¥.51743(1). 155 feet above base of London Clay ; 
Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 42-5 by 43^ ; length of 
infundibular processes 24-29^ ; length of slender processes up to ig\i. Range : 
diameter of central body 42-57^ ; length of infundibular processes 24-401X ; width 
of infundibular processes up to g\i proximally, 34^ distally ; length of slender 
processes up to 27[x ; number of specimens measured, 4. 

Description. This species has very distinctive infundibular processes with an 
irregular digitate margin, each branch being further split up into evexate, bulbous 
or bifid secae. The secae and/or the digitae may be inter-connected, thus giving rise 
to a fenestrate structure. The tabulation reflected by the infundibular processes is 
4', 6", 5'", ip, 1"". In addition there are some very slender processes, less than I[jl 
wide, restricted to the cingulum and sulcal zones. These processes are always 
closed, and are either acuminate or irregularly bifurcate. The exact number is 
variable and difficult to determine. 

P. pannosum has only been recorded from the Ypresian of Britain. 

Remarks. This species differs from Oligosphaeridium palcherrimum (Deflandre 
& Cookson) from the Australian Lower Cretaceous, in the nature of the fenestrate, 
infundibular processes. The slender cingular and sulcal processes are a character- 
istic feature. 

OTHER SPECIES 

Perisseiasphaeridium eisenacki sp. nov. The specimens described and figured by 
Eisenack (1958 : 402, pi. 26, figs. 1, 2) as Hystrichosphaeridium anthophorum Cookson 
& Eisenack from the Lower Cretaceous of Germany are here considered to belong to 
the genus Perisseiasphaeridium nov. and have been renamed accordingly. 

Evitt (1961) pointed out that Eisenack's specimens possess definite fine cingular 
processes whereas the type material from the Upper Jurassic of Australia and Papua 
has a barren cingular zone and has been attributed to the genus Oligosphaeridium 
(see p. 77). 

Genus LITOSPHAERIDIUM nov. 

Derivation of name. Greek, litos, plain or simple ; sphaera, ball — with 
reference to the simple arrangement of the processes on the surface of the central body. 

Diagnosis. Chorate cysts with spherical to sub-spherical central body composed 
of two membranes. Processes few in number (only one per plate area), hollow and 
open distally except for sulcal processes which may be closed. Reflected tabulation 
3', 6", 5'", ip, 1"", with variable number of sulcal processes. Archaeopyle apical. 



.so 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Type species. Hystrichosphaeridium siphoniphorum Cookson & Eisenack 1958. 
Probably Lower Cretaceous (Albian) ; Australia. 

Remarks. The presence of three apical processes and the absence of cingular 
processes is diagnostic of this genus, and makes it easily recognizable. The sulcal 
processes may be either absent or few. 



Litosphaeridium siphoniphorum (Cookson & Eisenack) 
PI. 7, figs. 7, 8 ; Text-figs. 16, 17 

1958. Hystrichosphaeridium siphoniphorum Cookson & Eisenack : 44, pi. 11, figs. 8-10. 

1963. Hystrichokolpoma sp. B., Baltes : 587, pi. 6, figs. 6-8. 

1963. Hystrichokolpoma sp. A., Baltes : 587, pi. 6, figs. 1-5. 

1964. Hystrichosphaeridium siphoniphorum Cookson & Eisenack ; Cookson & Hughes : 48, 

pi. 9, fig- 15- 

Emended diagnosis. Spherical to sub-spherical central body composed of thin 
endophragm and thick reticulate periphragm. Processes, composed of smooth 
periphragm, varying considerably in shape and size but commonly cylindrical or 
sub-conical and always hollow. Distal margin of processes entire or serrate. 
Hexagonal apical archaeopyle usually present. Number of processes 13, rarely 14 
or 15, in specimen possessing an archaeopyle. Inferred tabulation 3', 6", 5'", ip, 
1"" and o-2s. 

Holotype. National Museum of Victoria, Australia, specimen no. P17468, from 
Gingin Area, W.A., Seismic shot hole B2 at 230 ft. Horizon — probably Albian. 

Dimensions. Holotype : overall diameter 76^, diameter of central body 43^, 
length of processes c. ig-24[x. Paratype : overall diameter 69(0., diameter of central 
body 33[x, length of processes c. 14^., operculum width 21\l. 





Fig. 16. Litosphaeridium siphoniphorum (Cookson & Eisenack). A specimen from the 
Cenomanian. Left, apical view, showing the six-sided archaeopyle and the arrangement 
of the processes ; right, antapical view. x c. 450. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 81 

Range of British Cenomanian forms : diameter of central body 21-47(1 (mean 34.(1), 
length of processes 4—25(0.. Number of specimens measured, 160. 

Description. The periphragm of the central body at first sight appears to be 
granular, but at high magnification is seen to be reticulate. The processes, though 
normally cylindrical or subcorneal, can be mammiform or even saucer-shaped 
(Text-fig. 17), the latter being 4~5(x in height. Very occasionally closed processes 
are present being either apical processes or small sulcal processes. 

L. siphoniphorum has been recorded from the Albian of Australia and Roumania, 
and the Cenomanian of Australia and Britain. 

Remarks. The British Cenomanian specimens from Surrey agree fairly closely 
with the examples from Australia. The Surrey specimens appear to be smaller, but 
unfortunately the range of the Australian forms was not given in the description so 
no true size comparison can be made. 





Fig. 17. Litosphaeridium siphoniphorum (Cookson & Eisenack). A figure illustrating 
the variation in the size and shape of the processes (based on specimens from the Ceno- 
manian) . 



8> MKSOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 

Baltcs (1963) illustrated two forms (A and B) of this species from the Albian of 
Roumania. His species A has a central body diameter of 45-50^ and species B one 
of approximately 25fz. In Britain it is interesting to note that the mean of the 
central body diameter (34[x) falls midway between these two forms. Thus it seems 
likely that L. siphoniphorum in Britain is represented in Roumania by two geo- 
graphical subspecies, corresponding to Baltes' two forms, A and B. 



? Litosphaeridium inversibuccinum sp. nov. 
PL 12, fig. 3 

Derivation of name. Latin, inversi, inverted ; buccina, trumpet — referring 
to the trumpet-like shape of the processes. 

Diagnosis. Sub-spherical or ovoidal central body, not exceeding 20^1. in diameter, 
with sub-conical processes. Processes open distally, with denticulate or aculeate 
margin. Archaeopyle apical. 

Holotype. B.M.(N.H.) slide ¥.51744(1). Metropolitan Water Board Borehole 
No. 11 at 83-25 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 17 by 19^, length of processes 
7~9[x, number of processes 13. Range : diameter of central body n-igjx, length of 
processes 4 — g\i. Number of specimens measured, 8. 

Description. The wall of the central body is usually thin, but thick walled 
specimens have occasionally been encountered. The processes are not in connection 
with the interior of the central body and seldom exceed 15. The larger processes are 
sub-conical and may be up to iO[i wide at the base, rapidly decreasing in width to 
approximately 1-5-2^, before expanding distally into a denticulate or aculeate 
margin. In addition to these stout processes there are usually one or two slender 
ones which are possibly closed distally. The latter are probably sulcal processes. 
An apical tetragonal archaeopyle was seen in one specimen, the archaeopyle being 
surrounded by 6 precingular processes. However the remaining tabulation is 
obscure. 

Remarks. ? Litosphaeridium inversibuccinum sp. nov. is easily distinguishable 
by its size and the form of its processes. It is tentatively placed in the genus 
Litosphaeridium because it possesses the correct number of processes to give the 
diagnostic tabulation of this genus, although the arrangement of the processes has, 
as yet, not been elucidated and a detached apical region has not been observed. 
The form of the processes and of the archaeopyle are both similar to those structures 
in L. siphoniphorum. 

OTHER SPECIES 

The following species are here tentatively referred to the genus Litosphaeridium 
on the basis of the number and type of processes : 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 83 

? Litosphaeridium crassipes (Reade 1839). Upper Cretaceous ; England. 
? Litosphaeridium flosculus (Deflandre 1937). Upper Cretaceous ; France. 
? Litosphaeridium truncigerum (Deflandre 1937). Upper Cretaceous ; France. 



Genus CORDOSPHAERIDIUM Eisenack 1963& : 261 

Emended diagnosis. Sub-spherical chorate cysts, with central bodies composed 
of two distinct layers, periphragm variably developed, forming well developed 
processes, tubiform to buccinate, solid or hollow, intratabular and reflecting a 
tabulation of 1', 6", 6c, 6"', (ip), 1"" and a variable number of sulcal processes. 
Apical archaeopyle haplotabular never possessing zig-zag margin. 

Type species. Hystrichosphaeridium inodes Klumpp 1953. Eocene ; Germany. 

Remarks. The genus Cordosphaeridium differs from related genera in the form 
of the archaeopyle. The archaeopyle has the shape of a convex triangle with 
rounded corners. At first sight it appears to be precingular but by study of the 
process arrangement it has been shown to be apical in position. It is formed by the 
loss of the single apical plate, the resulting archaeopyle being termed haplotabular 
(latin, haplo, single). The processes are usually strongly fibrous and can be either 
open or closed distally. There is little differentiation in the size of the processes, the 
cingulum processes being often, but not constantly, larger. The number of processes 
per plate within this genus varies considerably and it is probable that at a later date 
it will be necessary to sub-divide this genus taking this fact into account. 

This genus was proposed by Eisenack (19636) for forms possessing characteristically 
fibrous processes. Since it has been shown that hystrichospheres are cysts of 
dinoflagellates, the systematics of this group should be based on the tabulation 
reflected by the arrangement of the processes. It is therefore considered that the 
reflected tabulation is a better diagnostic feature than the fibrosity of the processes 
and the diagnosis has been emended accordingly. Other reasons against using the 
fibrosity of the processes as a generic distinction are that it is very variable within 
this genus and also that fibrous processes have been observed in other genera which 
have a distinct and different tabulation. 



Cordosphaeridium inodes (Klumpp) 
PL 3, fig. 9 ; Text-fig. 18 



1953 
1953 
1955 
1961 

1963 
1963 



Hystrichosphaeridium truncigerum Cookson : 114, pi. 2, figs. 21-23. 
Hystrichosphaeridium inodes Klumpp : 391, pi. 18, figs. 1, 2. 
Hystrichosphaeridium inodes Klumpp ; Deflandre & Cookson : 277, pi. 8, fig. 7. 
Hystrichosphaeridium inodes Klumpp ; Gerlach : 186, pi. 28, figs. 4-6. 
Hystrichosphaeridium inodes Klumpp ; Brosius : 40, pi. 5, fig. 5. 
Cordosphaeridium inodes (Klumpp) Eisenack : 261, pi. 29, fig. 3. 



«4 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Description. C. inodes has a fibrous body wall, bearing processes which give the 
reflected tabulation typical of this genus. The variability in the number of processes, 
noticed by Klumpp, has also been observed in the London Clay forms, especially in 
the sulcal region. The processes are either hollow, open distally with an ellipsoidal 
cross-section or taeniate. The process walls of the London Clay specimens are 
extremely fibrous and appear to be thinner than in the type material, perhaps due to 
oxidation within the sediment. 

C. inodes has been recorded from sediments ranging from the Lower Eocene to 
Middle Miocene in age. 

Material (Figured). B.M.(N.H.) slide ¥.51745(1). 2 feet above base of London 
Clay ; Whitecliff, Isle of Wight. 

Dimensions. V. 5 1745 : diameter of central body 46 by 48^, length of processes 
19-24PL. Range in type material (Klumpp 1953) : diameter of central body 52-76^, 
length of processes 20-40jx. Range of London Clay forms : diameter of central 
body 46-7610., length of processes i4-33fx. Number of specimens measured, 5. 



Cordosphaeridium gracilis (Eisenack) 
PI. 3, fig. 8 ; PL 11, figs. 4, 6, 7 ; Text-fig. 19 

1938. Hystrichosphaera cf. ramosa (Ehr.) ; Eisenack : 186, text-fig. 1. 

1954. Hystrichosphaeridium inodes subsp. gracilis Eisenack : 66, pi. 3, fig. 17 ; pi. 10, figs. 

3-8 ; 112, figs. 7, 21. 
1961. Hystrichosphaeridium inodes subsp. gracilis Eisenack ; Gerlach: 187, pi. 28, fig. 6. 
1963&. Cordosphaeridium inodes subsp. gracilis (Eisenack) Eisenack, pi. 29, fig. 2. 





Fig. 18. Cordosphaeridium inodes (Klumpp). A specimen from the London Clay, 
apical view ; right, antapical view, by transparency. x c. 650. 



Left, 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



85 



Emended diagnosis. Spherical to sub-spherical fibrous central body bearing 
small number of fibrous processes. Processes cylindrical, solid, erect, simple or 
branched and distinctly digitate ; intratabular, one per plate area, number never 
less than 19 or greater than 20. Archaeopyle apical, haplotabular, and reflected 
tabulation that of the genus Cordosphaeridium. 

Holotype. Slide PH. 10. Geologisch-Palaontologisches Institut der Universi- 
tat Tubingen. Lower Oligocene ; Germany. 

Material (figured). B.M.(N.H.) slide ¥.51746(1). 173 feet above base of 
London Clay ; Sheppey, Kent. 

Dimensions. Holotype : diameter of central body jj\l, overall diameter i66(jl, 
length of processes 46-52(1. Range : diameter of central body 45-90^, (mean 69(1.), 
overall diameter 115-176^. ¥.51746(1) : diameter of central body 64 by 69^, 
length of processes 33-37jx. Range of London Clay specimens : diameter of 
central body 50-71(1, length of processes 20-43(1. Number of specimens measured, 
12. 

Description. The central body is characterized by a thick two-layered wall 
which is up to 2[x in thickness. The processes are strongly fibrous the fibres radiating 
outwards from the base of the processes over the surface of the central body, and 
when branched have a characteristic Y-shape. The single sulcal process is always 
included within the cingulum series. 

Remarks. This species was originally described and figured by Eisenack (1938c) 
as Hystrichosphaera cf. rantosa. Eisenack (1954) proposed a sub-species of Hystri- 
chosphaeridium inodes to include these forms on the basis of similar wall structure. 
The processes were described as solid, with fibrous branched endings, and the outer 
layer of the wall of the central body could be thicker than the inner one. The 
narrow hollow space in the interior of the processes at their base and passing through 
to the inner wall layer that Klumpp observed in H. inodes was not perceived with 
certainty by Eisenack for H. inodes gracilis. Eisenack (1954) noted and figured the 




Fig. 19. Cordosphaeridium gracilis (Eisenack). A specimen from the London Clay. 
Left, apical view ; right, antapical view, by transparency. x c. 650. 



86 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

archaeopyle and the operculum with a single process (plate 10, fig. 8). Gerlack 
(1961) similarly noticed a " pylome " in H. inodes gracilis (plate 28, fig. 6). In 1963, 
Eisenack transferred H. inodes and H. inodes gracilis to the new genus Cordosphae- 
ridium. 

Because of the observed differences to C. inodes, namely the variable thickness of 
the periphragm and endophragm, the absence of a narrow hollow space at the base 
of the processes, the solid structure and peculiar branching of the processes, it is felt 
that Eisenack's subspecies merits raising to the specific level. 

All of Eisenack's findings are verified in the London Clay specimens. Apart from 
their larger size, Eisenack's and Gerlack's forms are identical with the London Clay 
examples. 



Cordosphaeridium fibrospinosum sp. nov. 
PI. 5, %• 5 

Derivation of name. Latin, fibra, fibrous ; spinosus, thorny — with reference to 
the fibrous spines. 

Diagnosis. Ovoidal central body with wall up to o-5[x thick, composed of 
smooth endophragm and fibrous periphragm. Processes fibrous, often very broad 
and ovoidal in cross-section, walls perforate. Processes open distally, with entire or 
undulose margin. One process per plate reflecting a tabulation typical of genus. 
Archaeopyle apical haplotabular. 

Holotype. B.M.(N.H.) slide ¥.51747(1). Metropolitan Water Board Borehole 
No. 11 at 53 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 63 by 6y\i, length of processes 
i5-28[x, width of processes 5-25^. Range : diameter of central body 59-72^, 
length of processes up to 39[x, width of processes up to 26[x. Number of specimens 
measured, 5. 

Description. This species is characterized by fibrous, often perforate, processes 
which can be latispinous. The perforations show no regularity in arrangement and 
tend to be elongate. The cross-section of the processes is ovoidal or rarely cylindrical 
and then only in the narrower processes. The lengths of the processes vary consider- 
ably in different specimens but rarely exceed half the diameter of the central body. 
It should be noted that in the broader processes, the width often exceeds the length. 

C. fibrospinosum sp. nov. has been recorded throughout the London Clay of 
England. 

Remarks. The short, perforate processes, varying considerably in width but 
often very wide, make C. fibrospinosum an easily distinguishable species. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 87 

Cordosphaeridium cracenospinosum sp. nov. 
PI- 3. %• 4 

Derivation of name. Latin, cracens, graceful or slender; spinosus, thorny — 
with reference to the appearance of the processes. 

Diagnosis. Sub-spherical to polygonal central body with wall composed of 
endophragm and periphragm, up to i'5(x in thickness. Endophragm very thin. 
Archaeopyle apical haplotabular ; processes slender, buccinate, erect, or curved, 
solid or with fine central tubule or hollow, the last two types open distally. Distal 
margins foliate, bifurcate or digitate. Processes one per plate area. 

Holotype. B.M.(N.H.) slide ¥.51748(1). Metropolitan Water Board Borehole 
No. 39 at 170 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 122 by I25fi, length of 
processes up to 66[x. Range : diameter of central body 75-125^, length of processes 
17-76^. Number of specimens measured, 5. 

Description. The large central body of C. cracenospinosum sp. nov. has a finely 
reticulate surface. In overall outline this species appears to be sub-spherical, but 
closer examination shows that often it tends to be polygonal. The processes are 
generally single, rarely branched, and in length often exceed half the diameter of the 
central body. The periphragm often forms a ridge on the surface of the central body 
where a process arises. Occasionally very fine, shorter processes are present. 
Many of the processes are solid, others having a narrow central cavity throughout 
their length or being hollow tubiform. Distally there is considerable variation, 
digitate endings being the commonest. 

This species of Cordosphaeridium has been observed in samples throughout the 
London Clay of England. 

Remarks. C. cracenospinosum differs from C. gracilis by its thinner wall, which is 
only very faintly fibrous, the shape of the central body and the occasional presence 
of smaller, very fine, processes. It is unusual in having solid and hollow processes, the 
former however predominate. Process endings comparable to those in Baltisphae- 
ridium pectiniforme Gerlack (1961) from the Oligocene of Germany, are occasionally 
encountered. 

Cordosphaeridium exilimurum sp. nov. 
PI. 11, fig. 2 

Derivation of name. Latin, exilis, thin or meagre ; murus wall — with refer- 
ence to the rather thin wall of the central body. 

Diagnosis. Ovoidal central body, composed of thin, smooth or slightly granular 
endophragm with fine fibrils of periphragm running over surface. Processes 
tubiform or buccinate, of variable width, and rarely latispinous, distally open with 
serrate or undulose margin. Wall of processes thin and often fenestrate. 



88 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Holotype. B.M.(N.H.) slide ¥.51749(1). 275 feet above the base of London 
Clay ; Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 44 by 54^, length of processes 
i8-26[x. Range : diameter of central body 44-98^, length of processes 16-42}/. 
Number of specimens measured, 7. 

Description. Haplotabular archaeopyle and tabulation characteristic of the 
genus Cordosphaeridium. The number of processes per plate area is one, but 
occasionally a fine subsidiary process may be present. Fine processes also occur in 
the sulcal region. Both the endophragm and periphragm are extremely thin, 
especially the latter when forming the processes. The wall of the processes is 
smooth or fibrous ; in the former the fibrils are only faintly developed. Whether 
or not the processes are always fenestrate is difficult to determine, even at high 
magnification, on account of the thinness of the periphragm. The processes rarely 
exceed half the diameter of the central body ; they are up to I0[j. wide meridionally 
and distally extremely expanded. Adjacent processes are occasionally united 
distally. 

C. exilimurum has been recorded throughout the London Clay of England. 

Remarks. No other described species possesses fine, often perforate processes 
with an apical haplotabular archaeopyle and tabulation 1', 6", 6c, 6'", 1"" and a 
variable number of sulcal processes. ?C. cantharellum (Brosius 1963) is similar in 
general form but possesses stronger, more cylindrical processes which are never 
perforate or united distally, and often have a recurved distal margin. 

Cordosphaeridium latispinosum sp. nov. 

PI. 5, ng. 8 

Derivation of name. Latin, latus, broad ; spinosus, thorny — with reference to 
the very wide processes present in this species. 

Diagnosis. Ellipsoidal central body having a finely striate periphragm from 
which arise two types of processes : broad ovoidal to quadrate ones, closed or with 
restricted distal opening, and slender oblate processes. Larger processes reflecting a 
tabulation of 1', 6", 6'", 1"" ; smaller ones restricted to sulcal and cingulum regions. 

Holotype. B.M.(N.H.) slide ¥.51746(2). 173 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 56 by 6i(x, length of processes 
up to 22(x. Range : diameter of central body 50-77^, length of processes 11-24}/., 
width of broad processes up to 2j)x. Number of specimens measured, 5. 

Description. The broad processes of Cordosphaeridium latispinosum sp. nov. 
are quadrate or ellipsoidal in cross-section proximally. They taper distally and have 
a slightly fibrous wall which may be perforate with small lateral spines : the broad 
processes are found on the apical, pre- and postcingular, posterior intercalary and 
antapical plate areas. The slender processes appear to be sulcal or cingular processes. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 89 

They can be simple or bifurcate, distally they are oblate or accuminate. The 
striae on the periphragm radiate outwards from the bases of the processes over the 
surface of the central body. 

C. latispinosum has been recorded from the London Clay of Sheppey, Kent and 
Enborne, Berkshire. 

Remarks. C. latispinosum differs from ? Litosphaeridium truncigerum Deflandre 
1937 from the Upper Cretaceous of France, in the nature of the broad processes. 
In ?L. truncigerum these are widely open with denticulate margins, whereas in 
C. latispinosum they are closed or have a restricted elongate opening with lateral 
spines developed. 

Cordosphaeridium divergens (Eisenack) 
PI. 12, fig. 2 

1938. Hystrichosphaeridium sp., Eisenack : 185, text-fig. 3. 

1954. Hystrichosphaeridium divergens Eisenack : 67, pi. 9, figs. 13-16. 

1963. Baltisphaeridium divergens (Eisenack) Downie & Sarjeant : 91. 

19636 Cordosphaeridium divergens (Eisenack) Eisenack : 262, pi. 29, fig. 4. 

Description. Specimens of C. divergens from the London Clay possess an apical 
haplotabular archaeopyle and the tabulation of the genus Cordosphaeridium. 
Eisenack (1954) noted and figured the archaeopyle and correctly indicated that the 
margin of it lay parallel to the equator. Specimens having a reticulate surface, as 
observed by Eisenack from the Oligocene, are also found in the London Clay. The 
processes are intratabular, there being at least 4 on each precingular area. In 
structure they compare favourably with those of the type material. 

Material (Figured). B.M.(N.H.) slide ¥.51750(1). 157 feet above the base of 
London Clay ; Whitecliff, Isle of Wight. 

Dimensions. ¥.51750(1) : diameter of central body 45 by 47[x, length of proces- 
ses i4-22fx. Range of London Clay forms : diameter of central body 38-52^, 
length of processes 12-21 fx. Number of specimens measured, 5. 

Remarks. C. divergens superficially resembles Baltisphaeridium cf. intermedium 
Deflandre (1938) from the Oxfordian, differing only in its slightly larger size. As yet 
species belonging to the genus Cordosphaeridium have not been recorded from 
horizons earlier than the Eocene. 

Cordosphaeridium multispinosum sp. nov. 
PI. 3, fig. 6 

Derivation of name. Latin, multi, many or numerous ; spinosus, thorny — 
with reference to the numerous processes. 

Diagnosis. Sub-spherical to ovoidal central body. Thin endophragm and 
fibrous periphragm giving rise to numerous, more than 45, short fibrous processes. 



go MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Processes taeniate, solid, undulose with serrate or digitate distal margins, sometimes 
arranged in meridional rows, sometimes haphazard in position. 

Holotype. B.M.(N.H.) slide ¥.51751(1). 173 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 56 by 59fA, length of processes 
up to i5[i. Range : diameter of central body 45-59^., length of processes up to 24^. 
Number of specimens measured, 4. 

Description. The processes are numerous, generally simple with parallel edges 
expanding proximally and distally. Some of the processes are regularly linked 
proximally in such a manner as to give rise to six long rows, running from apex to 
antapex. Between these rows the arrangement of the other processes appears to be 
haphazard. There appear to be 2, rarely 3, processes per plate area. The maxi- 
mum width of the processes is j\l, and their length one-quarter to one-third (rarely up 
to one-half) the diameter of the central body. Occasionally fine, acuminate proces- 
ses are present on the central body. There is a well developed archaeopyle with an 
uninterrupted margin. 

C. multispinosum sp. nov. has been recorded from the London Clay of Whitecliff 
Bay, Isle of Wight, Hampshire and the Isle of Sheppey, Kent. 

Remarks. In the linear arrangement of some of the processes and the haphazard- 
ous nature of others C. multispinosum differs from all other species of Cordosphae- 
ridium. 

?Cordosphaeridium fasciatum sp. nov. 
PI. 7, figs. 5, 6 

Derivation of name. Latin, fasciatus, striped — with reference to the striped 
appearance of the central body due to the thickenings of the periphragm. 

Diagnosis. Spherical to sub-spherical central body composed of reticulate 
endophragm of fibrous periphragm. Processes, composed of periphagrm, smooth or 
slightly fibrous, short, wide and tubiform, always hollow and denticulate distally. 

Holotype. B.M.(N.H.) slide ¥.51719(1). Speeton Clay, Shell West Heslerton 
Borehole No. 1, Yorkshire, at 42-5 metres depth. Lower Cretaceous (Lower 
Barremian). 

Dimensions. Holotype : diameter of central body 40 by 40(0., length of processes 
n-i6fx, number of processes 19. Range : diameter of central body 35-47(a, length 
of processes 12-25^. Number of specimens measured, 6. 

Description. From the base of each process, thickenings of the periphragm 
radiate over the surface of the central body joining together with similar thickenings 
from neighbouring processes. The reticulate nature of the endophragm can some- 
times be observed where the periphragm thins midway between processes and also at 
the bases of the processes when one is able to view directly down the centre of a 
vertical process (PI. 7, fig. 6). The processes have parallel or sub-parallel sides 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 91 

throughout their length. There are 18 to 20 processes, an apical archaeopyle 
usually being present. The shape and form of the archaeopyle is difficult to deter- 
mine and a detached apical region has not, as yet, been observed. However the 
archaeopyle is thought to be haplotabular and the spines to have an inferred reflected 
tabulation of 1', 6", 6c, 5'", 1"" and o-2s. 

?C. fasciatum sp. nov. has only been recorded from the Lower Barremian of 
Yorkshire. 

Remarks. The short, wide tabular processes differentiate this species from 
?C. eoinodes (Eisenack) and the nature of the periphragm on the central body is 
probably different although this was not commented on in the original diagnosis or 
description. The nature of the periphragm on the surface of the central body and 
when composing the processes of Hystrichosphaeridium radiculum sp. nov. and 
H. mantelli sp. nov. is very similar to C. fasciatum perhaps indicating a relationship 
between the three species. Each form possesses a distinctive type of process and the 
two forms of Hystrichosphaeridium have a greater number of processes than does 
C. fasciatum. The type of archaeopyle is a very important factor in determining 
the above relationships but unfortunately the exact type of archaeopyle has not 
been determined as yet. 

?C. fasciatum is thought to belong to Cordosphaeridium on account of the probable 
presence of a haplotabular archaeopyle, the number of processes and the fibrous 
nature of the periphragm so commonly observed in species of this genus. 

OTHER SPECIES 

The following species are here tentatively referred to the genus Cordosphaeridium 
Eisenack 1963, emend, on the basis of the number and type of processes: 

? Cordosphaeridium cantharellum (Brosius 1963). Oligocene ; Germany. 

? Cordosphaeridium difficile (Manum & Cookson 1964). Upper Cretaceous ; 

Arctic Canada. 
1 Cordosphaeridium diktyoplokus (Klumpp 1953). Eocene ; Germany. 
? 'Cordosphaeridium diktyoplokus subsp. latum (Klumpp 1953). Eocene; Germany. 
1 Cordosphaeridium eoinodes (Eisenack 1958). Lower Cretaceous ; Germany. 
7 Cordosphaeridium erectum (Manum & Cookson 1964). Upper Cretaceous ; 

Canada. 
? Cordosphaeridium floripes (Deflandre & Cookson 1955). Miocene ; Australia. 
? Cordosphaeridium floripes subsp. breviradiatum (Cookson & Eisenack 1961). 

Eocene ; Australia. 
} Cordosphaeridium microtriaina (Klumpp 1953). Eocene ; Germany. 

Genus POLYSPHAERIDIUM nov. 

Derivation of name. Greek, polys, many ; sphaero, ball — with reference to the 
central spherical body which bears numerous processes. 

Diagnosis. Chorate cysts possessing sub-spherical to ovoidal central body and 
bearing numerous processes all similar in size. Number of processes per plate area 



92 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

greater than one, not normally more than four. Processes hollow, open or closed 
distally, process cavity not connecting with interior of central body. Archaeopyle, 
when present, apical with angular margin. 

Type species. Polysphaeridium subtilum sp. nov. Eocene (Ypresian) ; England. 

Remarks. The processes are typically fairly short and expand distally, termina- 
ting by a serrate or spinous margin. The number of processes present makes it 
extremely difficult for the reflected tabulation to be determined, but is undoubtedly 
basically the same as that possessed by Hystrichosphaeridium tubiferum (Ehr). 

As this genus now stands it contains a large number of species having in common 
an archaeopyle and a large number of hollow processes, but otherwise unrelated. 
At some future date, fuller knowledge of this genus will undoubtedly necessitate its 
subdivision, perhaps on the basis of process form. 

Polysphaeridium subtile sp. nov. 
PI. ii, fig. i 

Derivation of name. Latin, subtilus, thin or slender — with reference to the 
slenderness of the processes. 

Diagnosis. Central body, sub-spherical to sub-rectangular, with wall composed 
of extremely thin smooth endophragm and thin granular periphragm. Processes 
not in connection with interior, slender, open distally, with serrate margin. Average 
length of processes, one-fifth to one-third the diameter of central body. Number of 
processes greater than 60. 

Holotype. B.M.(N.H.) slide ¥.51752(1). 178 feet above base of London Clay; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 47-48^, length of processes 
io-i6jx. Range : diameter of central body 3i-5-50jx, length of processes 6-i6jx. 
Number of specimens measured, 5. 

Description. Simple, slender, tubiform processes possessing a usually serrate 
distal margin. The latter is occasionally entire, and may be circular or oval. 
The width of the processes never exceeds 2\i. The processes do not appear to be 
arranged in any regular pattern. 

Remarks. P. subtile sp. nov. is distinguished from all other species by the 
number and form of the open processes present. 

Polysphaeridium pastielsi sp. nov. 
PI. 4, fig. 10 

1948. Hystrichosphaeridium pseudhystrichodinium (Deflandre) ; Pastiels : 43, 3, figs. 12-15. 

Derivation of name. In honour of Andre" Pastiels, who made pioneer studies in 
the Eocene microplankton of Belgium. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 93 

Diagnosis. Ovoidal central body with smooth or granular surface. Apical 
archaeopyle with zig-zag margin. Processes numerous, all of one type ; simple 
open, tapering distally to narrow neck before spreading slightly to an opening with 
entire or serrate margin. Processes sometimes united proximally, slightly fibrous. 

Holotype. B.M.(N.H.) slide V. 51753(1). 99 feet above base of London Clay ; 
Sheppey, Kent. 

Dimensions. Holotype : diameter of central body 37-43^, length of processes 
10-14^. Range : diameter of central body 31-43^, length of processes up to ig\i. 
Number of specimens measured, 5. 

Description. The processes broaden proximally, often quite considerably, and 
may measure up to 9 [i. in width but the latter is very variable. An apical archaeo- 
pyle is present. 

Remarks. The Ypresian forms illustrated by Pastiels (1948) as Hystricho- 
sphaeridium pseudohystrichodinium strongly resemble the London Clay forms. The 
holotype of Deflandre has long supple processes, thinning regularly towards the 
extremity which is simple, or fluted, or with a very small fork. P. pastielsi is 
therefore a separate species which superficially resembles H. pseudohystrichodinium. 

IP. asperum (Maier) is described as having an oval granular central body. The 
processes are open, tapering, terminating distally in 2-3 spines. This distal margin 
is not unlike the denticulate lip sometimes observed in P. pastielsi. The two species 
may even be conspecific. 

P. simplex (White) as illustrated by Gerlach (1961) and by Brosius (1963) are both 
probably conspecific with P. pastielsi. They differ from White's holotype which 
possesses longer and fewer processes with greatly expanded distal openings. 



Polysphaeridium pumilum sp. nov. 
PI. 7, figs. 3, 4 

?i955. Hystrichosphaeridium recurvation (White) ; Deflandre & Cookson : 269, pi. 1. fig. 12. 

Derivation of name. Latin, pumilus, dwarfish or little — with reference to the 
small size of this species. 

Diagnosis. Subspherical central body having numerous small open tubular 
processes. Processes terminating distally in a slightly recurved more or less entire 
margin. Length of processes less than half that of the maximum body diameter. 

Holotype. Geol. Surv. Colin, slide PF.3037(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey at 750 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : overall diameter 40 by 34^, diameter of central body 
25 by I9[jl, length of processes 8-iO[i.. Number of processes c.44. Range : overall 
diameter 30-40^, diameter of central body 17-25^, length of processes 7-iojj., 



94 MF.SOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 

width of processes i-i-5[x, number of processes 38-44. Number of specimens 
measured, 3. 

Description. The central body has a smooth surface. The processes are 
tubular with a thin wall. They widen slightly both proximally, at the junction with 
the central body, and distally up to about 2jjl. The distal termination of a process 
superficially strongly resembles that of Hystrichosphaeridium sheppeyi sp. no v., but 
on closer examination the presence of spines has not been observed. The distal 
margin is probably entire or slightly denticulate. The number of processes present 
indicate that each precingular and postcingular plate area bears two processes. An 
archaeopyle has not been observed with certainty. 

Remarks. This species is clearly differentiated from all other species by its size 
and the number and type of processes present. It appears to be very similar to 
Deflandre & Cookson's second series of specimens described as Hystrichosphaeridium 
recurvatum (White) ; however the Australian examples of Lower Cretaceous age 
seem to be larger, although the correct number of processes for the species is present. 
Deflandre & Cookson (1955, pi. I, fig. 12) illustrate a specimen with seemingly similar 
processes to the British Cenomanian examples. 

Polysphaeridium laminaspinosum sp. nov. 

PL 8, fig. 8 

Derivation of name. Latin, lamina, blade ; spinosus, thorny — referring to the 
flattened blade-like appearance of the processes. 

Diagnosis. Spherical to sub-spherical central body composed of reticulate 
endophragm. Processes numerous, approximately 36 in number, composed of 
periphragm ; cylindrical, smooth and delicate, terminating in entire margin. 
Characteristic circular impression occurring where process arises from central body. 

Holotype. Geol. Surv. Colin, slide PF.3052. Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 650 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : diameter of central body 27 by 2J\l, length of processes 
ii-i5[jl, number of processes 36. Range ; diameter of central body 23-28^, length 
of processes ix-ij\x. Number of specimens measured, 6. 

Description. The endophragm appears to be granular until examined under 
high magnification when the reticulate nature becomes apparent. The processes are 
broadly tubular, up to 5fz in width, usually flattened and are often bent. A few of 
the processes are clearly truncated at their distal extremity, but most splay out 
slightly and have a corrugated entire margin. A 6-sided apical archaeopyle has been 
observed in one specimen. The number of processes present indicate that there are 
two per plate. 

P. laminaspinosum is a rare species found throughout the Cenomanian of Fetcham 
Mill, Surrey. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 95 

Remarks. The size, number and nature of the processes make it easy to distin- 
guish P. laminaspinosum from all previously described species. The processes are 
longer and more distinctly tubular than is usual for this genus. If more species of 
this form are discovered a new genus should be erected to differentiate these types 
from the typical species of Polysphaeridium. 



OTHER SPECIES 

The following species are here tentatively referred to the genus Polysphaeridium 
on the basis of the form of the processes although an apical archaeopyle has not been 
recorded in any of them. 

? Polysphaeridium asperum (Maier 1959). Miocene ; Germany. 

1 Polysphaeridium deflandrei (Valensi 1947). Middle Jurassic ; France. 

? Polysphaeridium cf. elegantulum (Wiler 1956). Tertiary ; Germany. 

? Polysphaeridium fabium (Tasch, McClure & Oftedahl 1964). Lower Cretaceous ; 
U.S.A. 

} Polysphaeridium fluctuans (Pastiels 1948). Eocene ; France. 

? Polysphaeridium follium (Tasch, McClure & Oftedahl 1964). Lower Cretaceous ; 
U.S.A. 

1 Polysphaeridium fucosum (Valensi 1955). Cretaceous ; France. 

^Polysphaeridium marsupium (Tasch, McClure & Oftedahl 1964). Lower 
Cretaceous ; U.S.A. 

? Polysphaeridium major (Lejeune-Carpentier 1940). Upper Cretaceous ; Bel- 
gium. 

? Polysphaeridium patdinae (Valensi 1953). Middle Jurassic ; France. 

? Polysphaeridium perovatum (Tasch, McClure & Oftedahl 1964). Lower Creta- 
ceous ; U.S.A. 

IPolysphaeridium polypes {=H. recurvatum subsp. polypes Cookson & Eisenack 
1962). Lower-?Upper Cretaceous ; Australia. 

^Polysphaeridium rhabdophorum (Valensi 1955). Cretaceous ; France. 

IPolysphaeridium simplex (White 1842). Upper Cretaceous ; England. 

^Polysphaeridium tribrachiosum (Tasch, McClure & Oftedahl 1964). Lower 
Cretaceous ; U.S.A. 

IPolysphaeridium zoharyi (Rossignol 1962). Pleistocene ; Israel. 



Genus DIPHYES Cookson 1965 : 85 

Emended diagnosis. Chorate cysts with ovoidal to spherical central body 
composed of two layers. Processes numerous, 1 to 4 per plate area, hollow and 
either open or closed distally. Large antapical process occurring opposite apical 
archaeopyle. 

Type species. Hystrichosphaeridium colligerum Deflandre & Cookson 1955. 
Eocene ; Australia. 



g6 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Remarks. The genus Diphyes is here restricted to include forms possessing two 
types of processes — numerous fine ones and a single large antapical. D. nudum 
Cookson does not possess any processes at all and certainly does not belong in this 
genus. 

Diphyes colligerum (Deflandre & Cookson) 
PL 4, figs. 2, 3 



1953 
1955 
1962 

fig 
1963 
1965 



Hystrichosphaeridium sp. C. Cookson : 115, pi. 2, figs. 29, 30. 
Hystrichosphaeridium colligerum Deflandre & Cookson : 278, pi. 7, fig. 3. 
Hystrichosphaeridium colligerum Deflandre & Cookson ; Cookson & Eisenack : 44, pi. 

9- 

Baltisphaeridium colligerum (Deflandre & Cookson) Downie & Sarjeant : 91. 
Diphyes colligerum (Deflandre & Cookson) Cookson : 86, pi. 9, figs. 1-12. 



Emended diagnosis. Ovoidal to spherical central body with wall composed of 
thin endophragm and outer finely reticulate periphragm. Processes composed of 
periphragm, numerous, simple, hollow, open or closed distally. One single broad 
antapical process. Total number of processes exceeding 50. 

Holotype. P.16301, National Museum of Victoria, Australia. Princetown 
Member of Dilwyn Clay, Lower Eocene ; Point Ronald, Vic. Dept. of Mines bore, 
Victoria. 

Material (Figured). B.M.(N.H.) slide V.5i754(i). 157 feet above base of 
London Clay ; Whitecliff Bay, Isle of Wight. 

Dimensions. Holotype : diameter of central body 33[x, overall diameter 56^, 
length of antapical process 20[x, width of antapical process 13(1, length of small 
processes approx. I3fx. Range : diameter of central body 30-33(1., overall diameter 
56— 59(x, length of small processes approx. 13^. Figured specimens diameter of 
central body 33 by 37 - 5(Jt, length of antapical process i6(jl, width of antapical process 
i5jx, length of small processes n-i5[x. Range of English specimens : diameter of 
central body 29-41^, length of antapical process i6-2ifx, width of antapical process 
8-i5[x, length of small processes 8-i5(x. 

Description. An apical archaeopyle and the large antapical process enable 
easy orientation of specimens of this species. The antapical process is hollow, 
cylindro-conical, occasionally closed, and bears small tubules, 2-3^ long, towards the 
distal extremity. The tubules can take the form of simple conical protuberances or 
can have slightly bifurcate extremities. The smaller processes are commonly 
simple, occasionally united proximally, and may be open or closed distally. They 
are slender but do vary in width, and in specimens possessing open processes they 
taper to a distal neck before terminating with a sightly expanded opening. The 
distal margin may be finely serrate or entire. Both types of processes are slightly 
fibrous and do not communicate with the interior of the central body. There are 
commonly 4, regularly distributed, processes for each precingular plate area ; 2-4 
for the postcingular plate areas and a constant 2 in the cingular plate areas. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 97 

Remarks. The diagnosis of Diphyes has been emended to relate the process 
arrangement to a dinoflagellate tabulation, and to draw attention to the single 
antapical process. 

In the original diagnosis, the smaller processes are said to be closed. The figure 
by Deflandre & Cookson (1955, pi. 7, fig. 3) seems to indicate, however, that the 
processes are open, as in the examples from the London Clay. Cookson & Eisenack 
(1961, pi. 2, fig. 9) figured H. colligerum with the processes definitely open. The 
species may well be confined to examples with open processes after re-examination 
of the holotype. Cookson (1965, pi. 9, figs. 1-3) illustrates forms with distinctively 
larger antapical processes not unlike those of Litosphaeridium siphoniphorwm 
(Cookson & Eisenack) . Because of the larger size of this process she has incorrectly 
considered it to represent a second portion of the central body and has erected a new 
genus diagnosed as possessing bipartite cysts. The forms from the London Clay, 
the holotype of D. colligerum and the specimen illustrated by Cookson & Eisenack 
(196 1, pi. 2, fig. 9) are probably more typical of the species and show without doubt 
that the " posterior portion of the shell " is in fact an enlarged antapical process. 
This species has been recorded from the Upper Cretaceous (probably Senonian) and 
Eocene of Australia, and in England only from the Eocene. 

This species is easily distinguishable from all other types of dinoflagellate cysts. 



OTHER SPECIES 

The following species is here tentatively referred to the genus Diphyes on the basis 
of the numerous processes and single distinctive antapical process : 

? Diphyes monslruosum (Tasch, McClure & Oftedahl 1964). Lower Cretaceous ; 
U.S.A. 



Genus DUOSPHAERIDIUM nov. 

Derivation of name. Latin, duo, two ; sphaera, ball — with reference to 
the biospheroidal form of the test. 

Diagnosis. Proximate cyst composed of two more or less spheroidal parts, 
neither bearing processes. Anterior part with apical archaeopyle. Posterior part 
similar in shape with small circular antapical opening present. 

Type species. Diphyes nudum Cookson 1965. Upper Eocene ; Australia. 

Remarks. The type species was formerly placed in the genus Diphyes by Cookson 
(1965) because of the apparent resemblance of its posterior part to the antapical 
process of Diphyes colligerum. However, the latter is a chorate cyst whereas the 
former is proximate, a difference considered by the authors to be of profound 
significance in the development history of dinoflagellate cysts and thus to preclude 
classification in the same genus. 



98 



Ml SOZOIC AND CAINOZOIC DINOFL AGELL ATE CYSTS 

Genus TANYOSPHAERIDIUM nov. 



Derivation of name. Greek, tanyo, long or stretched out ; sphaera, ball — 
with reference to the elongate nature of the central body exhibited by this genus. 

Diagnosis. Chorate cysts with elongate central body composed of endophragm 
and periphragm, the latter also forming the processes. Processes cylindrical, open 
distally and arranged in more or less regular circular manner around central body. 
Number of processes variable, usually one or two (occasionally three) per plate area. 
Archaeopyle apical. 

Type species. Tanyosphaeridium variecalamum sp. nov. Upper Cretaceous 
(Cenomanian) ; England. 

Remarks. The marked feature of this genus is the elongate nature of the central 
body. Although the processes are arranged in a distinct circular manner on the 
surface of the central body, the tabulation is difficult to determine. The number of 
antapical processes, however, appears to be 3 or 6. Usually there is one or two proces- 
ses per plate area, but occasionally three may be present. Neither a detached apical 
region nor a complete specimen has, so far, been observed. 

Tanyosphaeridium variecalamum sp. nov. 

PL 6, fig. 7 ; Text-fig. 20 

Derivation of name. Latin, varius, different ; calamus, reed — with reference 
to the rather variable extremities of the processes. 




Fig. 20. Tanyosphaeridium variecalamum sp. nov. Holotype, lateral view, showing the 
circular arrangement of processes around the central body. x c. 1450. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 99 

Diagnosis. Elongate central body with granular surface. Processes, moderate 
in number, cylindrical, expanding slightly distally and terminating with serrate, 
aculeate or truncated margin. 

Holotype. Geol. Surv. Colin, slide PF.3035(2). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(Cenomanian). 

Dimensions. Holotype : length of central body 34(1, breadth 1451, length of 
processes 12-16(1, number of processes 26. Range : length of central body 30-43(1, 
breadth 14-20(1, length of processes 12-24(1. Number of specimens measured, 13. 

Description. The central body is composed of thin endophragm surrounded by 
granular periphragm. The processes are composed of smooth periphragm, and have 
an oval cross-section, there being characteristic oval areas on the surface of the central 
body beneath the processes, marking the initial divergence of the periphragm from 
the endophragm. The processes have fairly broad bases and taper distally before 
expanding slightly before terminating. Distally the processes may be truncated, 
terminate with one or two spines or splay out, the margin being serrate. The 
number of processes normally varies between 20 and 31, but one specimen has been 
observed with as many as 38. 

An apical archaeopyle is always present, surrounded by 6 precingular processes. 
Medially there is a definite ring of 6 cingular processes and therefore 9-14 processes 
on the hypotract. The arrangement of the hypotractal processes is difficult to 
interpret ; however there appears to be either 3 or 6 antapical processes. The 
number of sulcal processes appears to be 5-7. This species is therefore variable in 
the number of processes it possesses and is able to have either one or two processes 
per plate in certain areas. 

This species is present throughout the Cenomanian of England. 

Remarks. The only similar species is T. isocalamus (Deflandre & Cookson) 
from the Lower Cretaceous of Australia. The figures of the Australian form 
(Deflandre & Cookson 1955, pi. 2, figs. 7, 8) show that more processes are present than 
in T. variecalamum and that the extremities of the processes are more uniformly 
truncated. 

Tanyosphaeridium regulate sp. nov. 

PI- 3. %• 3 

Derivation of name. Latin, regularis, according to rule — with reference to the 
regular arrangement of the processes. 

Diagnosis. Elongate central body with granular surface, bearing numerous 
tubular, usually curved processes. Processes terminating with somewhat serrate 
margin. 

Holotype. B.M.(N.H.) slide "^.51755(1). 270 feet above base of London Clay ; 
Wbitecliff Bay, Isle of Wight. 



ioo MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Holotype : length of central body 36-5[x, breadth of central body 
23-5^, length of processes 14-10,(1, number of processes approximately 65. Range : 
length of central body 30-4410., breadth of central body 2i-24[x, length of processes 
12-igfx. Number of specimens measured, 4. 

Description. The periphragm of the central body is granular and bears a number 
of quite large tubercles. The periphragm of the processes is smooth. The proces- 
ses have relatively broad bases, up to 4[x wide and taper distally being i-i-5[jl wide 
for most of their length. At their distal extremities they widen slightly and have a 
somewhat serrate margin. The processes are arranged in circular series around the 
central body, indicating a reflected dinoflagellate tabulation. Two or, more rarely, 
three processes are present for each plate area. 

T. regulate has been recorded from the London Clay of Whitecliff Bay and of 
Enborne, Berkshire. 

Remarks. The distinctive elongate nature of the central body of T. regulare is 
typical of this genus. T. regulare differs from T. variecalamum in having more 
processes, and from T. isocalamus comb. nov. in having slenderer processes with 
more complex terminations. 

OTHER SPECIES 

The following species are here attributed to the genus Tanyosphaeridium on the 
basis of the shape of the central body and the form of the processes : 

Tanyosphaeridium ellipticum (Cookson 1965). Upper Eocene ; Australia. 
Tanyosphaeridium isocalamus (Deflandre & Cookson 1955). Lower Cretaceous ; 
Australia. 

Genus HOMOTRYBLIUM nov. 

Derivation of name. Greek, homos, same or similar ; tryblion, cup or bowl — 
with reference to the formation of two, almost equal, hemispheres after rupture of the 
cyst. 

Diagnosis. Sub-spherical chorate cyst with central body composed of thin 
endophragm and surrounding periphragm which gives rise to processes. Processes 
intratabular, cylindrical to tubiform, open distally, reflecting a tabulation of 3', 6", 
6c, 6'", ip, 1"" and 1 to 5s. Processes not in communication with cavity of the 
central body. Archaeopyle epitractal, suture running just above cingulum processes. 

Type species. Homotryblium tenuispinum sp. nov. Eocene ; England. 

Description. The genus Homotryblium is unusual in possessing an epitractal 
archaeopyle which has a compound operculum composed of the apical and precingu- 
lar plate series. It is an easily recognizable genus because of the nature of this 
archaeopyle and the possession of only 3 apical processes. Dinoflagellate cysts 
possessing epitractal archaeopyles are rare. Rhaetogonaulax gen. nov. and Dichado- 
gonyaulax gen. nov. are both described by Sarjeant, in a later section, as possessing 
epitractal archaeopyles ; 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 101 

Homotryblium tenuispinosum sp. nov. 
PI. 4, fig. ii ; PL 12, figs, i, 5, 7 ; Text-fig. 21 

Derivation of name. Latin, tenuis, thin ; spinosus, thorny — with reference to the 
rather slender processes. 

Diagnosis. Spherical central body with wall composed of thin layers — smooth 
inner endophragm, outer strongly granular periphragm. Processes erect or curved, 
tubiform, simple, open distally with serrate or aculeate margin, rarely perforate 
Width of processes variable. 

Holotype. B.M.(N.LL) slide ¥.51756(1). Metropolitan Water Board Borehole 
No. 11 at 53 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 41 by 48^, length of processes 
20-25(x. Range : diameter of central body 41-57^, length of processes i3-32fx. 
Number of specimens measured, 8. 




Fig. 21. Homotryblium tenuispinosum sp. nov. A specimen from the London Clay, 

antapical view, x c. 950. 



102 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Description. The processes are restricted to one per plate area and indicate a 
reflected tabulation of 3', 6", 6c, 5'", ip, 1"" and 1-5S. The equatorial and sulcal 
processes are frequently more slender than the others. Distally the processes often 
have a margin bearing short bifid aculei. The length of the processes is about half 
the diameter of the central body. The margin of the archaeopyle is interrupted on 
the epitract by a short projection, the sulcal tongue (Evitt). This has a correspond- 
ing sulcal notch on the hypotract. The number of sulcal processes varies from 1 to 5. 
In some specimens the plates readily separate, save for the three apicals which have 
never been observed as individual plates. 

H. tenuispinosum sp. nov. has only been recorded from the London Clay of England. 

Remarks. From the nature of the archaeopyle, the coarsely granular wall and 
the tabulation, H. tenuispinosum is distinct from all previously described species. 

Homotryblium pallidum sp. nov. 

PI. 12, figs. 4, 6 ; Text-fig. 22 

Derivation of name. Latin, pallidus, pale — with reference to the rather light 
colour of the central body after staining. 




Fig. 22. Homotryblium pallidum sp. nov. A specimen from the London Clay. Internal 
view of the epitractal operculum ; slender acuminate ancillary processes are present. 
X c. 950. 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 103 

Diagnosis. Sub-spherical to ovoidal central body composed of thin inner endo- 
phragm and granular periphragm. Processes of variable width, simple, tubiform, 
forming a circle where they arise from central body. Archaeopyle epitractal and 
processes reflecting generic tabulation. 

Holotype. B.M.(N.H.) slide ¥.51756(1). Metropolitan Water Board Borehole 
No. 11, at 53 feet depth, London Clay ; Enborne, Berkshire. 

Dimensions. Holotype : diameter of central body 45 by 48^, length of processes 
up to 25;jl Range : diameter of central body 40-49^, length of processes 16-34^. 
Number of processes 5. Number of specimens measured, 5. 

Description. H pallidum sp. nov. exhibits similar tabulation to H. tenuispino- 
sum of 3', 6", 6c, 5'", ip, 1"" with almost invariably only three sulcal plates. The 
central body, which takes stain only slightly having a very thin wall, has granules up 
to o-5ji. in height and o-5[x to 1 -5;x apart. The processes are cylindrical tubiform and 
in length closely approach the radius of the central body. Distally they are variable, 
in some specimens having an entire irregular margin, in others a serrate, aculeate or 
digitate margin. Besides the tubiform processes there are often present 1 to 5 
slender small acuminate processes. The latter can occur on the hypo- or epitract. 

This species has only been recorded from the London Clay of England. 

Remarks. H. pallidum differs from H. tenuispinosum in having a thinner wall, 
generally broader processes with more variable distal margins, and a well marked 
proximal circle where they arise from the central body. It also differs by having 
some very slender acuminate processes. The specimens with processes having 
entire circular or serrate margins appear to be closely related to Hystrichosphaeridium 
choanophorum Deflandre & Cookson (1954) from the Miocene of Australia, although 
Gerlack (1961) recognized what appears to be an apical archaeopyle in this species. 

Genus CALLAIOSPHAERIDIUM nov. 

Derivation of name. Greek, kallaion, cockscomb ; sphaera, ball — with 
reference to the crests or ribs on the surface of the central body. 

Diagnosis. Chorate cysts with sub-spherical central body composed of two layers. 
Processes intratabular and of two types : (i) cingular processes large and tubular, 
open distally, and (ii) apical, precingular, postcingular and sulcal processes solid. 
Antapical processes absent. Reflected tabulation inferred from arrangement of 
processes is 1' (—2'), 6", 6c, 5'", ip, 0"" and o-is. Thickenings of periphragm 
join all except cingular processes. Archaeopyle epitractal, suture just above 
cingular processes. 

Type species. Hystrichosphaeridium asymmetricum Deflandre & Courteville 
1939. Upper Cretaceous ; France. 

Remarks. The form of the processes, the epitractal archaeopyle and the absence 
of antapical processes make this a very distinctive genus. The thickenings of the 
periphragm joining the processes are also a noteworthy feature, though not peculiar 
to this genus. 



104 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Callaiosphaeridium asymmetricum (Deflandre & Courteville) 
PI. 8, figs. 9, 10 ; PI. 9, fig. 2 

1939. Hystrichosphaeridiimi asymmetricum Deflandre & Courteville : 100, pi. 4, figs. 1, 2. 

Description. This species, previously recorded only from the Senonian flints of 
France, has now been observed in the Speeton Clay of Yorkshire (Hauterivian and 
Lower and Middle Barremian) and in the Cenomanian of Surrey. All specimens 
agree fairly well with the original description given by Deflandre & Courteville 
(1939)- 

In the Barremian forms the large tubular processes tend to be considerably less 
spinous than the Upper Cretaceous forms and more globular, especially along the 
ribs. The term globular refers to small spherical spaces between the endophragm 
and the periphragm. In the Cenomanian examples, the distal spines may measure 
up to 20(j.. A noticeable feature in many of the British examples, not commented 
on in the original description, is the elevation of the ribs joining the hypotractal 
processes to form quite well developed septa. 

An archaeopyle is usually present, formed by the loss of the portion of epitract 
just above the tubular cingular processes. The five postcingular processes are 
joined by ribs forming a pentagon from which radiate ribs to the cingular processes. 
Along one of these ribs are usually situated two processes — one posterior intercalary 
and one sulcal. The apical region possesses a hexagon of 6 precingular processes and 
an apical process which is sometimes deeply divided and arises from the centre of the 
hexagon. The reflected tabulation therefore is : 1' (—2'), ? 6", 6c, $'" , ip, o"" and 
o-is. 

Dimensions. Holotype : diameter of central body about 40[x, length of tabular 
processes 22-34^. Range of Speeton Clay forms : diameter of central body 34-43^, 
length of cingular processes ii-20jx. Number of specimens measured, 4. Range 
of Cenomanian forms : diameter of central body 37-58^, length of cingular processes 
io-32|i.. Number of specimens measured, 5. 



OTHER SPECIES HITHERTO PLACED IN H Y ST R I C H OSPH A E R I D I U M 

The following species formerly attributed to Hystrichosphaeridium Deflandre 1937 
are here removed from this genus and referred to the following genera : 

Achomosphaera alcicornu (Eisenack 1954). Oligocene ; E. Prussia, USSR. 

Achomosphaera grallaeforme (Brosius 1963). Oligocene ; Germany. 

? Achomosphaera hirundo (Eisenack 1958). Lower Cretaceous ; Germany. 
Hystrichosphaera leptoderma (Maier 1959). Oligocene ; Germany. 

? Hystrichokolpoma xiphea (Maier 1959). Oligocene ; Germany. 
Cymatiosphaera membranacea (Philippot 1949). Oligocene ; Germany. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 105 

CONCLUSIONS 

The characteristics and known stratigraphical distribution of the 10 genera here 
considered are summarized in the accompanying Table. At present, the strati- 
graphic distribution of the genera cannot be correlated coherently with the variation 
in structure. As more species are attributed to these genera and the stratigraphic 
range of each genus becomes better known perhaps evolutionary relationships will 
become more obvious. 

At present no species belonging to these genera have been found earlier than the 
Middle Jurassic. Three genera are present in the Upper Jurassic ; Polysphaeridium, 
perhaps a primitive form, bearing numerous processes, and Hystrichosphaeridium 
and Oligosphaeridium both reflecting similar tabulations and possessing 4 apical 
processes. From the latter two genera perhaps are derived the remaining genera 
with the exception of Diphyes. After the Jurassic, although the tabulation remained 
basically the same, the number of apical plates appears to have become more 
variable and is probably an important systematic character. The genera Diphyes, 
Cordosphaeridium and Homotryblium have not been recorded, with certainty, from 
the Mesozoic. 

Dinoflagellate cysts belonging to the genera discussed are relatively abundant 
from the Upper Jurassic to the end of the Eocene, but appear to become less common 
thereafter. After more detailed morphological studies have been performed their 
importance to world-wide stratigraphy should be considerable. 



io6 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



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MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 107 

VI, DINOFLAGELLATE CYSTS WITH GON YA ULA X — TYPE TABULATION 

By W. A. S. SARJEANT 

INTRODUCTION 

The dinoflagellate genus Gonyaulax was originally proposed by Diesing (1866) in 
the following terms : 

" Animalcula solitaria libra symmetrica. Corpus immutabile, ovatum, 
ecaudatum, ciliatum, lorica, tabulata, sulco, hiante transversali in pagina 
dorsali obliquo in pagina ventrali bis geniculato et altera longitudinali, ab 
anfracto anteriori sulci transversalis ad extremitiatum anticam excurrenti, 
tripartita inclusum cilii e sulcis prominentibus. Os terminale. Flagellum 
unum pone os. Anus .... Ocellus nullus. Partitio ignota. Mariolae." 

The type species selected was G. spinifera (Claperide). An amended and much 
fuller diagnosis was subsequently proposed by Kofoid (191 1) : 

" Body variously shaped, spheroidal, polyhedral, broadly fusiform, elongated 
with stout apical and antapical prolongations, or dorsoventrally flattened. 
Apex rounded or truncate symmetrically or asymmetrically, never acutely 
symmetrically pointed. Antapex rounded, flattened, or pointed symmetrically 
or asymmetrically. Girdle usually equatorial, descending, displaced distally 
one to seven times its own width, and sometimes with slight overhang. Trans- 
verse furrow impressed or not ; longitudinal furrow usually slightly indenting 
the epitheca, often flaring distally, well developed, reaching to or approaching 
the anatpex. Thecal wall consisting of one to six apical plates (i'-6'), none to 
three anterior intercalaries (ia-3a), six precingulars (i"-6"), six girdle plates 
(ig-6g), six postcingulars (i'"-6'"), one posterior intercalary (ip) and one 
antapical (1""). The longitudinal furrow occupies the whole of the ventral area, 
which slightly indents the epitheca and consists of one anterior, about four 
intermediate, and one posterior plate. The midventral plate (1') of the apical 
series is usually a narrow plate extending posteriorly to a junction with the 
anterior plate of the ventral area, thus parting precingulars 1" and 6". When 
guarded by lateral ridges it simulates an anterior extension of the longitudinal 
furrow. It bears at its apex a delicate extension, the closing platelet which 
cover the apical region. 

Surface smooth or rugose with major thickenings along suture lines and minor 
ones on plates forming a regular or irregular polygonal mesh of varying size, often 
with vermiculate longitudinal elements predominating, sometimes spinulate. 
Furrows with or without lists which in many species are ribbed or spinulate. 
One or more antapical spines sometimes present, rarely with sheathed spines of 
the Ceratocorys type. Plates porulate, with pores in centres, angles or nodes of 
the mesh. A peculiar large ventral pore occurs to the right of the midventral 
line, usually near the suture between apical 1' and the plate to its right. Theca 
divided obliquely in fission. Ecdysis frequently seen. Chromatophores yellow 
to dark brown, often dense. In fresh, brackish and marine waters from boreal 
to tropical regions." 



io8 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Fossil forms, from the Upper Jurassic (Oxfordian) of France, were first attributed 
to this genus by Deflandre (1938). A tabulation pattern corresponding exactly to 
that of Gonyaidax was found to be exhibited by four species, which were named 
G. jurassica, G. cladophora, G. eisenacki, and G. pachyderma. A feature noted was 
the frequent absence of precingular plate 3", but the significance of this was not 
immediately recognized. A subsequent study by Deflandre of French Kimmeridgian 
sediments yielded further new species with the characteristic tabulation : and 
subsequent studies by various authors showed that fossils with a tabulation of this 
type were present from the Upper Triassic to the Oligocene, attaining greatest 
abundance in the Upper Jurassic and Lower Cretaceous. 

A number of other genera with a corresponding or closely similar tabulation have 
since been proposed. The genus Ctenidodinium was proposed by Deflandre (1938) 
for Upper Jurassic forms having a strong, denticulate crest on the posterior margin 
of the cingulum, but with only a low ridge on its anterior margin. These forms 
split by schism along the line of the cingulum. Klement (i960) demonstrated that 
the tabulation of these forms corresponded to that of Gonyaidax and proposed 
abandonment of the name Ctenidodinium. 

The genus Lithodinia was formulated even earlier (Eisenack 1935) for forms with a 
partially silicified shell from the Middle Jurassic (Dogger) of the Baltic. Subse- 
quently Eisenack (1961) stated that he considered Lithodinia to be congeneric with 
Gonyaidax. The author was courteously allowed to examine the genotype of 
Lithodinia during a visit to Tubingen in 1962 ; the tabulation certainly corresponds 
closely to the Gonyaidax pattern. 

The genus Microdinium was proposed by Cookson & Eisenack (i960) for forms 
having a tabulation pattern as follows ; 1', 6", ?6c, 6'", ip, 1"", the shell opening by 
loss of the apical plate. This tabulation accords with that specified by Kofoid (191 1) 
and the genus is thus technically invalid ; however, the majority of fossil species 
attributed to Gonyaulax have three to four apical plates. 

The genus Hystrichosphaera, which has a Gonyaulax-type tabulation, is treated 
with in an earlier section. There are in addition six other described fossil genera 
showing a tabulation resembling, but not exactly corresponding to, that of Gonyaulax : 

Cryptarchaeodinium Deflandre 1939, described from the French Upper Jurassic 
(Kimmeridgian), has the tabulation 4', 6", 7'", i-?2p, ?i"". This differs from that of 
Gonyaulax in the presence of an extra postcingular plate and in the presence of three 
plates (not yet clearly designated) in the antapical region. 

Eisenackia Deflandre & Cookson 1955, described from the Lower Tertairy of 
Australia, has the tabulation ?3', 6", ? 6 c, 6'", i-2p, 1"". It differs from Gonyaulax, 
and corresponds to Cryptarchaeodinium, in having three plates in the antapical 
region, but differs from the latter genus in the possession of only two or three apical 
plates. 

Leptodinium Klement i960, described from the Upper Jurassic of Australia, has 
the tabulation 4', 6", ?6c, 5'", ip, 1"". It differs from Gonyaulax in the lack of any 
anterior intercalary plate and the presence of one fewer postcingular plate. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 109 

Pluriarvalium Sarjeant 1962, from the Upper Jurassic of England, has the tabula- 
tion 5', i-3a, 6", 6c, 6'", ip, ip.v., 1 — ?6p.c, 1"". It is characterized by possession 
of a posterior circle of small plates surrounding the antapex. 

Glyphanodinium Drugg 1964, from the Paleocene of California, has the tabulation 
?i', 5", 6c, 6'", ip, ip.v., 1"". It is distinguished by the possession of only five 
precingular plates and the lack of an anterior intercalary plate. 

There are in addition a number of genera whose tabulation is incompletely known 
but which appear comparable to the Gonyaulax type. Eodinia Eisenack 1936, 
from the Middle Jurassic of Germany, has a thick, porate wall and shows little sign 
of tabulation ; there is no true cingulum, a helicoid suture being present instead. 
Comparison to the Gonyaulax-type cysts is afforded by the overall shape and the 
presence of an apical horn. 

Rhynchodiniopsis Deflandre 1935, from the Upper Cretaceous of France, has 
raised, denticulate crests with spines arising at points of crest junction around the 
transverse furrow. The surface is reticulate : the tabulation undetermined. In 
shape and presence of an apical horn, it compares with the fossil cysts of Gonyaulax 
type : there are no apparent distinguishing characters. 

Raphidodinium Deflandre 1936, from the Upper Cretaceous of France, has about a 
dozen spines arising at crest nodes, these spines being of sufficient length to render 
this a chorate cyst. Sutures are, however, present : the tabulation has not been 
determined. 

Hystrichodinium Deflandre 1935, again from the Upper Cretaceous of France, is 
another spinose form, the spines arising from sutures in considerably greater 
numbers. The tabulation appears comparable to that of Gonyaulax but has 
hitherto remained undetermined. 

Belodinium Cookson & Eisenack i960, from the Upper Jurassic of Australia, has a 
circular cingulum, plates differentiated by raised crests, an apical horn and a " flat- 
tened, membranous expansion " on the hypotract. This genus appears inadequately 
characterized. This comment applies equally to Carpodinium Cookson & Eisenack 
1962&, from the Lower Cretaceous of Australia whose tabulation is incompletely 
known and whose other characters in no wise differ from those specified for Gonyaulax. 

Heliodinium Alberti 1961, from the Lower Cretaceous of Germany, resembles 
Hystrichodinium but has flattened, dagger-like processes arising from the crests. 
The tabulation is again undetermined but appears closely similar to that of Gonyau- 
lax. 

There are thus a considerable number of genera of fossil dinoflagellates which 
possess or approach the Gonyaulax tabulation pattern. Those forms directly allocated 
to the genus Gonyaulax were originally considered to be the fossil remains of the 
motile stage of that genera. It was nonetheless recognized that the shell wall 
characteristically contained an opening of some kind, formed by median fission or by 
loss of a plate or a group of plates. Following the demonstration by Evitt (1961) 
that the occurrence of such openings (archaeopyles) indicated cysts, it became clear 



no MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

that the fossil Gonyaulax species were in fact cysts. Subsequently Evitt & Davidson 
(1964) demonstrated from studies of modern dinoflagellates that the genus Gonyaulax 
formed cysts of more than one type, but certainly including chorate cysts attributable 
to the genus Hystrichosphaera ; and Sarjeant (1965, text-fig. 3) showed that the 
arrangement of processes in the chorate Lower Cretaceous species Oligosphaeridium 
(formerly Hystrichosphaeridutm) vasiforum indicated a Gonyaulax-type motile 
stage. 

A somewhat confusing nomenclatural situation thus presents itself. On the one 
hand, it is now clear that a single modern dinoflagellate genus, with a constant 
tabulation, may form cysts which are of such distinctly different morphology as to 
merit classification into different form-genera ; it is arguable, on this basis, that the 
cyst characters indicate different evolutionary lineages and fully justify splitting of 
the modern genus. On the other hand, should the modern genus be retained 
unamended, it might well be considered that retention of separate generic names for 
the fossil cysts, which are simply stages in the life cycle, is unjustifiable. 

The terms of the " International Code of Botanical Nomenclature " recognize the 
existence of genera of three types — natural " Linnaean " genera ; organ genera, 
representing either parts of plants or stages in their life cycles ; and form genera, 
defined on morphology alone. Certain genera of dinoflagellate cysts may prove, as 
in the case of Hystrichosphaera, to have a determinable relationship to a living genus 
defined on its motile stage. However, it remains to be proved that a particular cyst 
type can be produced only by one particular motile type ; it is entirely possible that 
the same cyst type might be produced by related, but different, motile types. The 
dinoflagellate cysts, whether recent or fossil, are best treated as form genera and spe- 
cies, unless or until special provisions are framed for their treatment. 

These problems have been discussed at length by Deflandre (1964), Evitt & David- 
son (1964) and Norris (1965). A first step towards their solution was taken by 
Deflandre (1964 : 5) : 

" . . . je place dans le genre Gonyaidacysta nov. gen. (generotype : Gonyaulax 
jurassica Defl. 1938) toutes les especes fossiles a tabulation de Gonyaulax 
representees par des theques a cotes saillantes plus ou moins ornementees 
(pectinees, epineuses, denticulees etc . . .) munie d'un archeopyle (3ieme 
plaque pre-equatorial)." 

This proposal provides a partial answer to the problem ; however, the fossil species 
previously classed into Gonyaidax include not only forms with a precingular archaeo- 
pyle formed by loss of plate 3", but also forms with apical, epitractal and cingular 
archeopyles. Moreover, the diagnosis remains too wide in terms of tabulation and 
overall morphology ; forms like Hystrichodinium and Heliodinium would become 
homonyms, should their tabulation be shown to correspond to that of Gonyaulax. 
A more restricted diagnosis of Gonyaidacysta is therefore proposed in the section that 
follows ; the status of the genera mentioned earlier is reviewed ; and new genera are 
set up to accommodate species which do not accord with the revised concept of 
Gonyaulacysta, either in tabulation, ornamentation or mode of archaeopyle formation. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS in 

A. Genera with precingular archaeopyle 

Genus GONYAULACYSTA Deflandre 1964 : 5 

Emended diagnosis. Proximate dinoflagellate cysts, spherical, ovoidal, ellip- 
soidal or polyhedral, with the tabulation 3-4', o-ia, 6", 6c, 6'", ip, 0-1 p. v., 1"". 
Cingulum strongly or weakly helicoid. Cingular plates (6c) well or poorly marked ; 
ventral surface may show division into additional small plates. Sulcus generally 
but not constantly extending onto epitract. Apical horn frequently, but not 
constantly present ; median and antapical horns lacking. Sutures in form of low 
ridges ; bearing crests of varied form (smooth denticulate or spinous ; perforate or 
imperforate) ; or marked by lines of spines of varied form. Height of spines or 
crests always less than \ of shell width. A precingular archaeopyle formed by loss 
of plate 3". (Archaeopyle not always present.) Surface smooth, granular, nodose, 
punctate or reticulate. 

Type species. Gonyaulax jurassica Deflandre 1938. Upper Jurassic (Oxford- 
ian) ; France. 

Remarks. The generic diagnosis is emended to include reference to tabulation 
and to exclude forms characterized by very high crests, very long sutural spines, or a 
general spine cover. Forms with high crests are referred to Heslerlonia gen. nov. ; 
forms with long sutural spines to Heliodinium, Hystrichodinium or Raphidodinium : 
and forms with a general spine cover to Acanthogonyaulax. Forms according to this 
diagnosis but with an apical archaeopyle are referred to Meiourogonyaulax ; forms 
with an epitractal archaeopyle to Rhaetogonyaulax and Dichadogonyaulax ; and 
forms with a cingular archaeopyle to Ctenidodinhim. 



Gonyaulacysta gongylos sp. nov. 

PL 13 figs. 1, 2 ; Text-fig. 23. 

1961. Gonyaulax sp., Sarjeant : 97, pi. 13, fig. 15 ; text-fig. 6. 

Derivation of name. Greek, gongylos, ball, in reference to the spherical shape. 

Diagnosis. A Gonyaulacysta having an almost spherical theca, with short blunt 
apical horn. Tabulation 4', ia, 6", 7c, 6'", ip, 1"" ; plate boundaries usually 
bearing low, denticulate crests, Plate 1' elongate and corresponding to anterior 
prolongation of sulcus ; plate 4' very small, occupying horn tip. Plate 1'" reduced 
and elongate ; its boundary with sulcus not marked by a crest. Sulcus and cingu- 
lum both relatively broad ; cingular plate 7c small and pentagonal in shape. 

Holotype. B.M.(N.H.) slide ¥.51708(2). Lowest Oxford Clay ; Castle Cliff, 
Scarborough, Yorks. Upper Jurassic (Lower Oxfordian). 

Dimensions. Holotype : overall length 47(a, length of horn 5[x ; overall breadth 
45pt. ; breadth of cingulum c. 5[x. The few other specimens seen proved too severely 
damaged for measurement, but appear of comparable dimensions. 



H2 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Descriptions. Theca almost spherical, but having a somewhat polygonal 
appearance because of the angularly set crests. The horn is tipped by plate 4' ; 
extensions of plates 1-3' form its base. The anterior intercalary plate, ia, is 
quadrate and separated from the horn by plate 3'. Of the six precingular plates, 
plate 6" is reduced, plate 3" notably large and forming the anterior dorsal surface. 
It is arguable whether there are five or six postcingular plates, since plate 1'" is 
defined only by the angles formed by plates 2'" and ip with the furrow and sulcus. 
Plate 3'" is large and forms the posterior dorsal surface : plate 2" is reduced to accom- 
modate the quadrate posterior intercalary plate. The antapex is occupied by a 
single polygonal plate. 

The cingulum is broad and laevorotatory, its two ends differing in antero-posterior 
position by the cingulum's width. A pentagonal plate is present between the sulcus 
and the more posterior end of the cingulum ; this is here designated plate 7c, but 
since its form does not correspond with that of the other cingular plates, a special 
name might be merited. The sulcus is narrow in its anterior portion, broadening to 
contact with the cingulum and thenceforward remaining of constant breadth in its 
posterior portion. 

The surface of the periphragm is generally smooth, but bears a sparse scatter of 
coarse granules. The crests are strong but low, with well marked denticulations, 
resembling in form crest type f. of Gonyaulacysta jurassica (cf. Sarjeant, 1961, 
text-fig. 1). 

Remarks. Gonyaulacysta gongylos sp. nov. is an unusually small species character- 
ized by its overall shape, its apical tabulation, and the presence of plate jg. Re- 
examination of the holotype under a more powerful microscope has led to a fuller 
elucidation of the structure, in particular with regard to the crest form and the 
pattern of postcingular plates (a presumed plate boundary being shown to be merely 
a fold). 




Fig. 23. Gonyaulacysta gongylos sp. nov. Tabulation. 

view. X c. 800. 



Left, ventral view ; right, dorsal 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



113 



This species remains infrequent, only a very few severely damaged specimens 
having been encountered subsequently. For this reason also, the character of the 
archaeopyle remains to be confirmed ; allocation to Gonyaulacysta is made on the 
basis of tabulation and general morphology. It shows a similarity to a group of 
Upper Jurassic-Lower Cretaceous species Gonyaulacysta jurassica, G. eisenacki, 
G. cretacea and G. helicoidea) in crest form and in the reduction of plate 1", but 
differs from them in shape and presence of plate 7c. 



Gonyaulacysta palla sp. nov. 
PI. 13, figs. 3, 4 ; Text-fig. 24 

Derivation of name. Greek, palla, ball, in reference to the overall shape. 

Diagnosis. A Gonyaulacysta with almost spherical theca and prominent apical 
horn. Tabulation 4', ia, 6", ?6c, ?7'", ip, 1"" ; plate boundaries demarcated by 
crests formed of very short spines arising from low ridges. Plate 1' elongate, 
occupying anterior prolongation of sulcus and relatively large ; plate 4' small, 
occupying horn tip. Sulcus and cingulum of moderate breadth. Plate 1'" small 
and quadrate : posterior intercalary plate correspondingly small. Plate 2'" some- 
what larger than plate 1'", but remaining markedly smaller than other postcingular 
plates. Number of postcingular plates probably seven, but presence of crest 
between plates 4'" and 5'" not confirmed. 

Holotype. B.M.(N.H.) slide ¥.51718(2). Speeton Clay, Shell West Heslerton 
Borehole No. 1, West Heslerton, Yorks., at 42-50 metres depth. Lower Cretaceous 
(Lower Barremian) . 

Dimensions. Holotype : overall length 62[i, length of horn, iojx ; overall 
breadth $o\x ; breadth of cingulum c.4(x. Range of dimensions observed ; overall 
lengths 60-64^, overall breadths 46-52^. 





Fig. 24. Gonyaulacysta palla sp. nov. Tabulation. Left, ventral view ; 
right, dorsal view. x c. 800. 



ii 4 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. Theca spherical, relatively thin-walled and apparently fragile ; 
of some 20 specimens seen, all had suffered damage additional to archaeopyle 
formation. The holotype is the best-preserved, but nonetheless shows a tear in 
median ventral position. Surface densely granular, the granulation rendering 
the low crests difficult to distinguish in lateral positions. 

Apical horn slender and relatively long, accounting for about J-th of the thecal 
length. Its tip is formed by plate 4', its base by plates 1 to 3'. Six precingular 
plates, with plate 6' reduced to accommodate the anterior intercalary plate. Either 
six or seven postcingular plates ; presence of the presumed boundary between 
plates 4" and 5" could not be completely verified in any specimen seen, through a 
combination of damage and unfortunate orientation. Plates 1'" and ip are both 
small : plate 2'" is also reduced and does not have a boundary with the antapical 
plate. The antapical plate has the appearance of being inclined towards the ventral 
face, but this may simply result from compression. 

The cingulum is of moderate breadth and strongly laevorotatory, its two ends 
differing in antero-posterior position by about one and a half times its breadth. 
The number of cingular plates is doubtful. The sulcus is short and of moderate 
breadth. 

All specimens seen have a precingular archaeopyle, formed by loss of plate 3". 

Remarks. In its combination of overall morphology and tabulation, Gonyaula- 
cysta palla differs from all other described species. The most closely similar species 
is G. ambigua (Deflandre), which has a similarly spherical shape and crests of compar- 
able character, but differs in having no comparable apical horn and a different 
ventral tabulation. 



Gonyaulacysta axicerastes sp. nov. 
PL 13, figs. 11, 12 ; Text-fig. 25 

Derivation of name. Greek, axon, axis ; kerastes, horned — hence, axially 
horned. 

Diagnosis. A Gonyaulacysta having a spheroidal shell with apical pericoel 
crowned by slender horn arising from periphragm. Second short horn, formed from 
both membranes, present at antapex. Tabulation ?4', ia, 6", 6c, 6'", ip, 1"" ; 
plate boundaries bearing high delicate crests. Cingulum and sulcus relatively 
narrow, sulcus somewhat sinuous and broadening posteriorly. 

Holotype. B.M.(N.H.) slide ¥.51727(1). Speeton Clay, Shell West Heslerton 
Borehole No. 1, West Heslerton, Yorks., at 39 metres depth. Lower Cretaceous 
(Middle Barremian). 

Dimensions. Holotype : overall length ji\l, breadth 6o(jl ; shell length 50[z, 
breadth 52^ ; width of cingulum c.5jx ; length of apical horn, 8(x ; length of antapi- 
cal horn, 7*5fi.. Other specimens seen too damaged for measurement. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



115 



Description. Shell spheroidal, slightly broader than long, with epitract sur- 
mounted by a dome-like outgrowth of the periphragm enclosing an apical pericoel. 
A slender, furcate horn arises from the apex. The dome-like structure arises from 
the confluent crests of the plates on the apical portion of the epitract ; position of 
three -? four apical plates and an anterior intercalary plate are indicated by dimples 
in this structure. Six precingular plates are present, plate 6" being of reduced size. 
Six postcingular plates are likewise present, with plate 1'" slightly reduced to accom- 
modate the posterior intercalary plate. A polygonal plate occupies the antapex ; 
from its centre arises a short, blunt antapical process. Slender spines at the angles 
sustain the crests surrounding the antapex ; these crests are not connected to the 
antapical process. 

The cingulum forms a strong laevorotatory spiral such that its two ends differ 
in antero-posterior position by more than twice its width. It is divided into six 
cingular plates. The sulcus is sinuous rather than sigmoidal : a median section along 
its line would touch the two ends of the cingulum but would not cut them. It is of 
moderate breadth in its epitractal portion, but widens as it approaches the antapex. 

The crests are high and delicate, with denticulate edges ; they are irregularly 
perforate, the perforations being so fine as to be almost imperceptible at high 
magnifications (x 1,000). The surface bears an irregular, sparse scatter of coarse 
tubercles, but is otherwise smooth. 

No archaeopyle has been observed. 





Fig. 25. Gonyaulacysta axicerastes sp. nov. Tabulation, 
right, dorsal view. x c. 1000. 



Left, ventral view 



no MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Remarks. In its possession of an apical pericoel, surmounted by a horn, Gonyau- 
lacysta axicerastes differs from all other species of the genus except G. cassidata. It 
differs from G. cassidata in the form of the central shell, which is more ovoid in the 
latter species ; the less markedly sigmoidal form of the cingulum ; the more slender 
shape of the apical horn ; the detail of ventral tabulation ; and the possession of an 
antapical horn. Scriniodinium apaletiim Cookson & Eisenack i960, from the Upper 
Jurassic of Australia, has an apical horn and pericoel of similar form but differs in 
having an antapical pericoel also. The tabulation of Scriniodinium apaletum has not 
yet been fully described. 



Gonyaulacysta helicoidea (Eisenack & Cookson) 

PL 13, figs. 7, 8 ; PL 15, figs. 8, 9 ; Text-fig. 26 

i960. Gonyaulax helicoidea Eisenack & Cookson : 2, pi. 1. figs. 4-9. 

Emended diagnosis. A Gonyaulacysta with spheroidal to ovoidal theca sur- 
mounted by blunt apical horn. Epitract longer than hypotract ; antapex flattened. 
Tabulation : 4', ia, 6", 6c, 6'", ip, ?i p. v., 1"" ; plates bordered by denticulate 
crests, varying considerably both in height and character of denticulation. Cingu- 
lum strongly spiral : sulcus sigmoidal, plates 6" and 1'" roughly L-shaped. Surface 
bearing irregular scatter of tubercles. 

Holotype. The specimen figured by Eisenack & Cookson (i960, pi. 1, fig. 4). 
I. C. Cookson Colin., Melbourne. Lower Cretaceous (Aptian or older) ; Lake 
Phillipson bore, South Australia, at 87 ft. 10 in. 

Material (figured). B.M.(N.H.) slide ¥.51718(1), Speeton Clay, Shell West 
Heslerton Borehole No. 1, West Heslerton, Yorks., at 42-5 metres depth, Lower 
Cretaceous (Lower Barremian). 

Dimensions. Holotype : overall length 78(1, breadth 56jx. Range of Australian 
specimens : overall length 62— 86fx, breadth 48-67(1. Figured specimen (Speeton 
Clay) : overall length 45 [jl, breadth 45^ ; shell length 38^, breadth 43^ ; length of 
horn 7(x. Range of English specimens : overall length 44-53(1, breadth 42-46(1.. 

Description. The shell shape varies from an ovoid to an oblate spheroid ; the 
length of the horn and the height and form of the crests are also very variable. 

Of the four apical plates, plate 1' occupies the anterior prolongation of the sulcus : 
it is long and narrow. An elongate anterior intercalary plate is present alongside it. 
The four apical plates together form the apical horn, their crests being confluent at 
its tip. Six precingular plates are present, with plate 6" small, elongate, and roughly 
L-shaped. Six post-equatorial plates are present, plate 1'" being roughly axe- 
shaped, with broad anterior and narrow posterior portions. A quadrate posterior 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



117 



intercalary plate is present. The single antapical plate is large and polygonal ; the 
crests surrounding it are supported at their junctions by spines. A posterior ventral 
plate may be present, but if so, its anterior boundary is ill-defined. 

The cingulum is relatively narrow and pronouncedly laevo-rotatory, its two ends 
differing in antero-posterior position by three times its width. The sulcus is markedly 
sigmoidal ; a median dorso-ventral section would thus cut both ends of the cingulum. 
Six cingular plates appear to be present ; the posterior end of the cingulum is 
separated from the sulcus by a small crescentic plate, poorly marked or indistinguish- 
able in many specimens and thus excluded from the diagnosis. The crests crossing 
furrows lack denticles. 

An irregular scatter of tubercles is present on the surfaces of the plates ; the 
number, density and situation of these tubercles varies greatly between individuals. 

A precingular archaeopyle is usually present, formed by loss of plate 3". 

Remarks. The diagnosis of Gonyaulacysta helicoidea is emended to include 
reference to the tabulation. This species is numerous in the assemblages from 39 
and 42-5 metres depth in the Speeton Clay ; although the English specimens are 
markedly smaller, there can be no doubt that they are conspecific with the Australian 
species. 

A closely comparable species, Gonyaulacysta cretacea (Neale & Sarjeant 1962) is 
present in somewhat earlier horizons (99-25 metres — Hauterivian) in the West 
Heslerton boring. This differs from G. helicoidea only in having a more markedly 
polygonal outline and in lacking tubercles. It seems probable that G. cretacea is 
ancestral to G. helicoidea. 

The form from the Lower Cretaceous of New South Wales, figured by Deflandre & 
Cookson (1956, pi. 1, fig. 6) as IGonyaulax sp. indet., may well be attributable to this 
species. 





Fig. 26. Gonyaulacysta helicoidea (Eisenack & Cookson). Tabulation. 
Left, ventral view ; right, dorsal view. x c. 800. 



n8 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Gonyaulacysta episoma sp. nov. 

PL 13, figs. 9, 10 ; Text-fig. 27 

Derivation of name. Greek, episomos, bulky, fat — referring to the rotund shell 
shape. 

Diagnosis. A Gonyaulacysta with spherical to broadly ovoid shell with strong 
apical horn of moderate length. Tabulation 4', ia, 6", ?5c, 6'", ip, 1 p. v., 1"". 
Crests consisting of rows of thin spinelets connected distally by trabeculum ; 
an extremely delicate membrane stretching between spinelets and trabecula. 
Cingulum strongly spiral ; sulcus broad and short, stretching from about mid-point 
on epitheca to about mid-point on hypotheca. Surface densely granular ; very few 
spines occasionally present. Horn with trifurcate appearance produced by high 
crest bounding plate 4'. 

Holotype. B.M.(N.H.) slide ¥.51730(1). Speeton Clay, Shell West Heslerton 
Borehole No. 1, West Heslerton, Yorks., at 19-25 metres depth, Lower Cretaceous 
(Upper Barremian). 

Dimensions. Holotype : overall length So[i, breadth 74^ ; shell length yo\L, 
breadth 68[jl ; horn lOfx in length ; crests c.2jx in height ; cingulum c.3\i broad. 
Range of dimensions : overall length 80-95^, horn length io-i8[jl, breadth 6o-8o[x. 

Description. An abundant species at this horizon, some 30 specimens having 
been examined. All show some degree of distortion as a result of compression of 
the originally spherical, fairly thin-walled shell. The horn is short, strongly tapering 
and pointed ; it is tipped by plate 4', the high crest bounding this plate producing a 





Fig. 27. Gonyaulacysta episoma sp. nov. Tabulation. Left, ventral view 
right, dorsal view. x c. 800. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 119 

characteristic trifurcate appearance. There are four apical plates, plate 1' occupying 
the anterior prolongation of the sulcus and being unusually broad. Six precingular 
plates are present, the sixth being reduced to accommodate the anterior intercalary 
plate. 

Six postcingular plates are present, plate 1'" being reduced to accommodate the 
posterior intercalary plate. A roughly quadrate posterior ventral plate separates 
the sulcus from the single large antapical plate. 

The cingulum is of moderate breadth and forms a strong laevorotatory spiral such 
that its two ends differ in antero-posterior position by three times its breadth. It 
comprises cetainly five, possibly six cingular plates. The sulcus is short and broad. 

The surface is densely granular. In at least one specimen (figured), a very few 
short spines are present on the surface of the hypotract : spines are not present, 
however, on the holotype. The degree of granulation of the sulcus is markedly less 
than that of the rest of the surface. 

A precingular archaeopyle, formed by loss of plate 3", is present in all specimens 
seen. 

Remarks. Gonyaulacysta episoma sp. nov. is characterized by its combination of 
shape, tabulation and crest character. Gonyaulacysta nuciformis (Deflandre 1938), 
from the Upper Jurassic, has a somewhat similar overall shape and degree of granu- 
lation, but the shell wall is thicker, the tabulation is less clear and the form of the 
crests is quite different. Gonyaulacysta scotti (Cookson & Eisenack 1958) an inade- 
quately described species from the Upper Jurassic of Western Australia, has rather 
similar crests, but has a more markedly ovoidal shape and an apical horn of dissimilar 
type. Gonyaulacysta tenuiceras (Eisenack 1958) from the Aptian of Germany, has a 
horn and crests of somewhat similar character, but the crests are much higher and 
the tabulation is markedly different. A specimen figured as G. tenuiceras by 
Alberti (1961, pi. 11, fig. 7), from the Upper Barremian of Germany, may well be in 
fact G. episoma. 

Gonyaulacysta hadra sp. nov. 
PL 14, fig. 1 ; Text-fig. 28 

Derivation of name. Greek, hadros, well-developed, bulky, stout — referring to 
the unusually large size. 

Diagnosis. A Gonyaulacysta with thick-walled, spherical to spheroidal shell and 
long, tapering apical horn. Tabulation 4', ?oa, 6", 6c, 6'", ip, 1 p.v., 1"" ; poorly 
marked by crests in form of very low ridges bearing well spaced, extremely abbreviate 
spinelets. Cingulum weakly spiral : sulcus short, confined to ventral region. 
Surface generally densely granular. 

Holotype. B.M.(N.H.) slide ¥.51731(1). Speeton Clay, Shell West Heslerton 
No. 1 Borehole at 19-25 metres depth, West Heslerton, Yorks., Lower Cretaceous 
(Upper Barremian). 



120 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Paratype. B.M.(N.H.) slide V.5i73o(5). Same locality and horizon. 

Dimensions. Holotype : overall length 151(1, breadth ny\i. Shell length 
117(1 ; length of horn 34^ ; breadth of cingulum c.yy.. Paratype : overall length 
145^, breadth c.i I2[x ; shell length 105^ ; length of horn 40^ ; breadth of cingulum 
c.5fx. Range : overall length 0.140-155(1. 

Description. This is an unusually large and very characteristic species, quite 
frequent at this horizon, some 20 specimens having been studied. The dense 
granulation and relatively inconspicuous character of the crests render the tabulation 
difficult to determine : Text-fig. 28 was prepared from study of several specimens 
and is unlikely to be accurate in detail. On most specimens, including the holotype, 
granules are absent from various small patches of the surface : this appears to 
result from damage. Granulation is consistently faint or lacking on the sulcus, 
which is somewhat sunken. 

The test is spherical to spheroidal and composed of two distinct layers ; a fairly 
thin periphragm and a thicker endophragm. The endophragm bulges only into the 
base of the apical horn, so that the horn contains a cavity between the wall layers. 




Fig. 28. Gonyaulacysta hadra sp. nov. Tabulation. Left, ventral view ; right, dorsal 
view. Insert : the wall structure at the apex, in diagrammatic section. x c. 550. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 121 

Four apical plates are present, jointly forming the apical horn. Plate i' is long 
and broad, occupying the anterior prolongation of the sulcus. An anterior inter- 
calary plate could not be determined. Six precingular plates are present, plates i" 
and 6" being reduced. There are also six postcingular plates, with plate i'" reduced 
to accommodate the large posterior intercalary plate. A narrow posterior ventral 
plate separates the polygonal antapical plate from the sulcus. 

The cingulum forms a feebly laevorotatory spiral, its two ends scarcely differing 
in antero-posterior position. The sulcus is short, extending only over the middle 
third of the ventral surface : it is widest at mid-point and tapers to anterior and 
posterior. 

A precingular archaeopyle, formed by loss of plate 3", is present in all specimens 
seen. 

Remarks. In general form, tabulation and crest character, Gonyaulacysta hadra 
sp. nov. differs from all described species. 



Gonyaulacysta orthoceras (Eisenack) 
PL 14, figs. 5, 6 ; Text-fig. 29 

1958. Gonyaulax orthoceras Eisenack : 388, pi. 21, figs. 3-14, pi. 24, fig. 1. ; text-figs. 2, 3. 

J 959- Gonyaulax orthoceras Eisenack ; Gocht : 54, pi. 5, figs. 12, 13. 

1961. Gonyaulax orthoceras Eisenack : Alberti : 6, pi. 11, figs. 1—3. 

1963. Gonyaulax orthoceras Eisenack ; Gorka : 30, pi. 3, figs. 1-4. 

Emended diagnosis. A Gonyaulacysta having an ovoidal theca of moderate wall 
thickness, with strong, tapering apical horn accounting for about one-fifth to one 
quarter of overall length. Tabulation 4', ia, 6", ?6c, 7'", ip, 1"" ; plate boundaries 
outlined by low crests bearing very abbreviate spinelets. Cingulum strongly 
spiral, of moderate breadth : sulcus broad and extending to antapex. Surface of 
shell granular to tuberculate. 

Holotype. The specimen illustrated by Eisenack (1958, pi. 21, fig. 5) from 
Preparation Ob. Apt. no. 32. Aptian glauconitic limestone, Deutschen Erdol A.G., 
Erdolwerke Holstein, boring Marne, Feld Heide, North Germany, at 761-7 metres 
depth. 

Material (figured). B.M.(N.H.) slide ¥.51730(3). Speeton Clay, Shell West 
Heslerton Borehole No. 1, West Heslerton, Yorks., at 19-25 metres depth. Lower 
Cretaceous (Upper Barremian). 

Dimensions. Holotype : overall length 95fi, breadth 71^ ; length of horn 22[x. 
Range of German specimens : overall length 70-105 [x. Figured specimen : overall 
length ioofi., breadth 8ojjl ; length of horn c.20[x ; width of cingulum c.5[x. Range 
of English specimens ; overall length 80-11 5 y.. 



122 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. Shell broadly ovoidal, with the hypotract rounded. The crests 
separating the four apical plates converge at the apex. Plate i' occupies the 
anterior prolongation of the sulcus and is markedly elongate. Six precingular plates 
are present, with plate 6" very reduced to accommodate an anterior intercalary plate. 
Seven postcingular plates are present , plates i " ' and 2 " ' being reduced to accommodate 
a rather indistinctly demarcated posterior intercalary plate. A single polygonal 
plate occupies the antapex. 

The cingulum forms a laevorotatory spiral such that its two ends differ in antero- 
posterior position by over three times its width. The number of cingular plates 
appears to be six, but the crests separating them are poorly marked. The sulcus is 
of moderate breadth and extends from mid-point on the epitract to the antapex. 

The shell wall is of moderate thickness and consists of two distinct layers. The 
apical horn is formed by the periphragm, the endophragm showing no outbulge ; 
the horn is thus hollow and contains what is effectively an apical pericoel. The 
English specimens have a densely granular surface, but lack tubercles such as are 
present on the German specimens. 

A precingular archaeopyle, formed by loss of plate 3", is generally present. 

Remarks. The diagnosis is emended to include reference to the tabulation. In 
his original diagnosis, Eisenack figures two alternative tabulation patterns and 





Fig. 29. Gonyaulacysta orthoceras (Eisenack). Tabulation. Left, ventral view 
right, dorsal view. x c. 750. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



123 



expresses doubt as to which is correct ; he comments on the difficulty of distinguish- 
ing crests from folds. The tabulation presented in Eisenack's Text-fig. 3 agrees 
closely with that determined from the English specimens. The plate here designated 
as postcingular plate 1'" is figured, but not numbered ; Eisenack's plates 1'" to 6'" 
thus correspond to plates 2'" to 7'" of the scheme here adopted. The presence of 
anterior and posterior intercalary plates is confirmed. 

Gonyaulacysta orthoceras (Eisenack 1958) is an abundant and characteristic 
Cretaceous species, having a known range from Upper Valanginian to Turonian. 
It is clearly distinguishable through its combination of shape, tabulation, and nature 
of crests : comparisons with other described species are discussed by Eisenack 
(1958 : 389) and Gorka (1963 : 31). 



Gonyaulacysta aichmetes sp. nov. 
PL 13, figs. 5. 6 ; Text-fig. 30 

Derivation of name. Greek, aichmetes, spearman, warrior ; referring to the 
pronounced apical horn. 





Fig. 30. Gonyaulacysta aichmetes sp. nov. Tabulation. Left, ventral view ; 
right, dorsal view. x c. 1000. 



1.-4 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Diagnosis. A Gonyaulacysta with ovoidal to broadly ellipsoidal theca and strong, 
tapering apical horn accounting for about one-sixth to one-seventh of overall length. 
Tabulation 4', ia, 6", 6c, 6'", ip, 1"". Crests delimiting plates represented by low 
ridges, minutely serrate ; those bordering cingulum higher. Cingulum strongly 
spiral, of moderate breadth ; sulcus sunken, broad, with only short epitractal section. 
Surface of shell densely granular ; granulation less pronounced on sulcus. 

Holotype. B.M.(N.H.) slide ¥.51730(2). Speeton Clay, Shell West Heslerton 
Borehole No. 1, West Heslerton, Yorks., at 19-25 metres depth. Lower Cretaceous 
(Upper Barremian). 

Dimensions. Holotype : overall length ioi[x, breadth 64^ (minimum) ; shell 
length 841X, breadth 56(1 (minimum) ; length of horn, i6[x ; width of cingulum 
c.4-5fx. Range of dimensions : overall length c.95-i05[x, breadth c. 55-65(1. 

Description. This is a relatively infrequent species, some 6 specimens only 
having been studied. The holotype was the best oriented for study, but is somewhat 
crushed in at right, so that breadth measurements stated are minima and the right- 
hand tabulation is possibly inaccurate, albeit confirmed in some measure by study of 
other specimens. • 

There are four apical plates ; the apical horn is tipped by plate 4', its flanks being 
formed by the other three plates. Plate 1' is especially elongate, extending down 
almost two-thirds of the epitract. Six precingular plates are present, plate 6'' being 
reduced to accommodate a very large anterior intercalary plate. Six post-cingular 
plates are present, with plate 1'" reduced and very elongate ; an elongate posterior 
intercalary plate lies between it and the antapex. A single, rather quadrate plate 
occupies the antapex. 

The cingulum forms a strong laevorotatory spiral such that its two ends differ in 
antero-posterior position by twice its width. It is bordered by strong ridges. The 
cingular plates are poorly defined, but appear to be six in number. The sulcus is 
broad and relatively short, extending to the antapex. 

The shell surface is densely granular. The crests are low but generally readily 
perceptible : they are finely but irregularly serrate. 

A precingular pylome, formed by loss of plate 3", is present in all specimens seen. 

Remarks. Gonyaulacysta aichmetes sp. no v. is of a general form similar to several 
other Cretaceous species, but is distinguished by shape, crest character and detail of 
the tabulation. The most comparable species is undoubtedly Gonyaulacysta 
apionis (Cookson & Eisenack 1958) from the Albian of South Australia. However, 
this latter species has a more ellipsoidal shape, smooth crests and four pronounced 
projections bordering the antapical plate ; its tabulation has not been fully specified, 
but, from the figures given (Cookson & Eisenack 1958, text-figs. 3, 4) plate 1 appears 
to be less elongate, there appears o be no anterior intercalary plate, and the posterior 
ventral structure appears different. The " lid " on the apical horn of G. apionis 
is probably simply a small apical plate edged by crests, such as is present in G. 
aichmetes. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 125 

Gonyaulacysta cassidata (Eisenack & Cookson) 
PI. 14, figs. 3, 4 ; Text-fig. 31 

i960. Gonyaulax helicoidea subsp. cassidata Eisenack & Cookson : 3, pi. 1, figs. 5, 6. 

1962. Gonyaulax cassidata Eisenack & Cookson ; Cookson & Eisenack : 486, pi. 2, figs, i, 2. 

1964. Gonyaulax cassidata Eisenack & Cookson ; Cookson & Hughes : 42, pi. 5, fig. 10 only. 

Emended diagnosis. A Gonyaulacysta with thin-walled, broadly ovoidal theca, 
surmounted by apical pericoel terminating in short horn. Tabulation 4', ia, 6", 6c, 
6'", ip, 1"" ; plate boundaries demarcated by high, delicate crests with smooth or 
denticulate edges. Cingulum strongly spiral, of moderate breadth : sulcus broaden- 
ing posteriorly, weakly sigmoidal. (A median dorso-ventral plane would barely 
intersect the two ends of the cingulum.) Surface of shell smooth or only minutely 
granular : irregular scatter of tubercles present in some specimens. 

Holotype. Specimen P. 17869, National Museum of Victoria, Australia. Lower 
Cretaceous (Albian) ; Santos's Oodnadatta bore, South Australia, at 327 feet depth. 

Material (figured). Geol. Surv. Colin, slide PF.3047(i). Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 730 feet depth. Upper Cretaceous 
(Cenomanian) . 





Fig. 31. Gonyaulacysta cassidata (Eisenack & Cookson) . Tabulation. Left, 
ventral view ; right, dorsal view, x c. 1000. 



126 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Holotype : overall length &3\i, breadth 52(1. Range of Australian 
specimens : overall lengths 71 to 9551, breadths 47 to 57^. Figured specimen : 
overall length 78^, breadth 53^, shell length 42^, breadth 45^. Range of English 
specimens : overall lengths 60 to 78^ breadths 46 to 53^. 

Description. Shell broadly ovoidal, the apical pericoel and high antapical 
crests imparting a polygonal appearance. The crests separating the four apical 
plates converge at the top of the apical horn, which has a bifid appearance. Plate 1' 
is elongate but relatively short, occupying the anterior prolongation of the sulcus. 
The apical pericoel comprises the apical plates, the anterior intercalary plate and the 
anterior portions of the six precingular plates : its volume is between one-third and 
two-thirds that of the shell proper. The anterior plate is somewhat elongate : 
plate 6" is reduced and almost triangular. Six postcingular plates are present. 
Plate 1'" is reduced and linear, difficult to see in many specimens : it is displaced by 
the posterior broadening of the sulcus. A small, quadrate posterior intercalary 
plate separates plates 1'" and 2'" from the single, polygonal antapical plate. 

The cingulum forms a laevo-rotatory spiral such that its two ends differ in antero 
posterior position by over twice its width. It is composed of six plates. The sulcus 
is of moderate breadth on the epitract but broadens considerably as it approaches 
the antapex. 

The shell wall and the crests are both delicate. The crests are high, typically but 
not consistently denticulate, sometimes minutely and irregularly perforate : the 
very high crests surrounding the antapex appear to be sustained by delicate spines 
at the angles. Tubercles may be present ; their number and distribution varies 
considerably between individuals. 

A precingular archaeopyle is formed by loss of plate 3" : in some specimens, 
including the figured specimen, the cingulum is slightly torn also. 

Remarks. The diagnosis is emended to include reference to the tabulation. 
The English specimens correspond closely to those figured from Australia, differing 
only in details of shape and proportionate size of shell and pericoel, features in which 
some degree of variation would be expected. 

Cookson & Hughes (1964) described this species from the Cambridge Greensand 
(?Albian-basal Cenomanian) : of two forms figured, one (p. 5, fig. 10) corresponds 
to Gonyaulacysta cassidata as here interpreted, the other (p. 5, fig. 11) appears to 
belong to Psaligonyaulax deflandrei sp. nov. (p. 137). Both species range right 
through the Cenomanian horizons of the Chalk of the Fetcham Mill Borehole, albeit 
consistently in low numbers only. 

Gonyaulacysta whitei sp. nov. 
PL 14, fig. 2 ; Text-fig. 32 

Derivation of name. Named in honour of two early workers on fossil micro- 
plankton — Henry Hopley White of Clapham, England, an amateur microscopist 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



127 



who described assemblages from the Chalk in 1842-44, and M. C. White of the 
United States, who described in 1862 the first Palaeozoic assemblages, from New 
York State. 

Diagnosis. A Gonyaulacysta having an ovoidal theca with short, blunt apical 
horn formed from both shell layers. Tabulation 3', ia, 6", 6c, 6'", ip, 1"" : plate 
boundaries demarcated by moderately high crests, densely and finely perforate, with 
straight or ragged edges. Cingulum broad, strongly spiral : sulcus sigmoidal, of 
moderate breadth but widening somewhat posteriorly. (A median dorso-ventral 
plane would barely intersect the two ends of the sulcus.) Surface of shell smooth or 
only very minutely granular. Crests bounding antapex supported at the angles by 
strong, broad spines. 

Holotype. Geol. Surv. Colin, slide PF. 3048(1), Chalk. 
Survey Borehole, Fetcham Mill, Surrey at 770 feet depth. 
(Cenomanian). 

Dimensions. Holotype : overall length 62[x, breadth 49^ : 
breadth 45-5 ; length of horn 9jx. 

Description. Shell rotund, lemon-shaped, the apical horn joining the shell so 
smoothly as to have no precise base. Only three apical plates, the crests bounding 
them forming a pimple on the tip of the apical horn. Plate 1' is elongate and occu- 
pies the anterior prolongation of the sulcus : its posterior boundary was not clearly 
determined. An anterior intercalary plate and six precingular plates are present, 
plate 6" being reduced and subtriangular. Six postcingular plates are present, 
plate 1'" being very small and having an ill-defined boundary with the sulcus. The 
single posterior intercalary plate separates plates 1'" and 2'" from the quadrate 
antapical plate. 



H.M. Geological 
Upper Cretaceous 

shell length 53[jl, 





Fig. 32. Gonyaulacysta whitei sp. nov. Tabulation. Left, ventral view 
right, dorsal view. x c. 1000. 



128 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

The cingulum forms a laevorotatory spiral such that its two ends differ in 
antero-posterior position by almost 4 times its breadth. Six cingular plates are 
present : the ends of plates ic and 6c extend somewhat into the sulcus. The 
epitractal portion of the sulcus is of moderate breadth ; the hypotractal portion 
broadens progressively as it approaches the antapex. 

A precingular archaeopyle is formed by loss of plate 3". 

Remarks. This species is based on a single specimen, well preserved and display- 
ed : its characters are considered sufficiently distinctive to justify creation of a new 
species. Shape, tabulation and crest character distinguish Gonyaulacysta whitei 
sp. nov. from all other described species. 



Gonyaulacysta fetchamensis sp. nov. 
PI. 15, figs. 1, 2 ; Text-fig. 33 

Derivation of name. Refers to the type locality, Fetcham Mill, Surrey. 

Diagnosis. A Gonyaulacysta having an ovoidal theca with strong, blunt apical 
horn formed by periphragm only. Tabulation 3-?4', ia, 6", 6c, 7'", 2p, 1"" ; 
sutures in form of low but well-marked, rather fibrous crests giving rise occasionally 
to short, blunt spines. Cingulum narrow, strongly spiral ; sulcus broad, sunken. 
Shell surface densely granular. 

Holotype. Geol. Surv. Colin, slide PF.3046(i). Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(basal Cenomanian). 

Dimensions. Holotype : overall length 12511, breadth io8[x ; shell length 95^, 
breadth o,8fx ; length of horn c.25[x. 

Description. This species is extremely infrequent : of three specimens encoun- 
tered, one (the holotype) is well preserved, the other two are severely damaged. 

The shell is broadly ovoidal, giving rise to a strong, blunt apical horn ; this horn is 
formed by the periphragm only and constitutes what is effectively an apical pericoel. 
There are certainly three and possibly four apical plates, presence of a crest separating 
plates 3' and 4' being unconfirmed. Plate 1' is unusually large and club-shaped. 
Six precingular plates are present, with plate 6" reduced to accommodate a sub- 
triangular anterior intercalary plate. Seven post cingular plates are present. 
Plates 1'" and 2'" are reduced to accommodate a large posterior intercalary plate, and 
plate 7'" is also reduced to accommodate a second, smaller intercalary plate. (The 
crest separating plates 5'" and 6'" is somewhat torn.) The antapex is occupied by a 
single plate of moderate size. 

The cingulum is narrow, forming a laevorotatory spiral such that its two ends 
differ in antero-posterior position by almost three times its width. The ends of the 
cingulum are widely separated by a very broad sulcus, which widens further in its 
posterior portion. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



129 




130 MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 

The crests are fibrous in nature, with close-set slits in places : they give rise to 
occasional short spines. In the holotype a broken line of " tubercles ", like an 
embryonic crest, crosses plate 5" ; this was not observed in the other specimens. 

A precingular archaeopyle is formed by loss of the large plate 3". In the holotype, 
the region round the archaeopyle is somewhat folded. 

Remarks. The generic allocation of Gonyaulacysta fetchamensis is questionable, 
in view of its possession of two posterior intercalary plates and a seventh postcingular 
plate. The similarity in general morphology to a number of Lower Cretaceous 
species of Gonyaulacysta resulted in its allocation to that genus ; however, it may 
subsequently prove preferable to erect a new genus for species having this tabulation 
pattern, a procedure not now adopted in view of the low numbers of specimens en- 
countered to date. 

The most closely comparable species is undoubtedly Gonyaulacysta orthoceras 
(Eisenack), which has a similar general form and apical horn. However, Gonyaulax 
fetchamensis is clearly distinguished by the form of its crests and the detail of ventral 
tabulation. 

OTHER SPECIES 

The following species are here attributed to the genus Gonyaulacysta on the basis 
of general structure and formation of an archaeopyle by loss of plate 3" : 

Gonyaulacysta aculeata (Klement i960). Upper Jurassic (POxfordian-Kimmerid- 
gian) ; Germany. 

Gonyaulacysta amabilis (Deflandre 1939). Upper Jurassic (Kimmeridgian) 
France. 

Gonyaulacysta ambigua (Deflandre 1939). Upper Jurassic (Kimmeridgian) 
France. 

Gonyaulacysta apionis (Cookson & Eisenack 1958). Lower Cretaceous (Albian) 
South Australia. 

Gonyaulacysta aptiana (Deflandre 1935). Lower Cretaceous (Aptian) ; France 

(see p. 140). 
Gonyaulacysta cladophora (Deflandre 1938). Upper Jurassic (Oxfordian) ; France. 

Gonyaulacysta clathrata (Cookson & Eisenack 19606). Upper Jurassic (PTithonian) ; 
Western Australia. 

Gonyaulacysta crassicornuta (Klement i960). Upper Jurassic (Kimmeridgian) ; 

Germany. 
Gonyaulacysta cretacea (Neale & Sarjeant i960). Lower Cretaceous (Hauterivian) ; 

England. 

Gonyaulacysta diaphanis (Cookson & Eisenack 1958). Cretaceous (? Aptian) ; 
Western Australia. 

Gonyaulacysta edwardsi (Cookson & Eisenack 1958). Cretaceous (Aptian- 
Turonian) ; Australia. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 131 

Gonyaulacysta eisenacki (Deflandre 1938). Upper Jurassic (Oxfordian) ; France. 

Gonyaulacysta eumorpha (Cookson & Eisenack 19606). Upper Jurassic (Oxfordian 
-Lower Kimmeridgian) ; Western Australia. 

Gonyaulacysta granulata (Klement i960). Upper Jurassic (Oxfordian-Kimmerid- 
gian) ; Germany. 

Gonyaulacysta granuligera (Klement i960). Upper Jurassic (Kimmeridgian) ; 
Germany. 

Gonyaulacysta hyalodermopsis (Cookson & Eisenack 1958). Lower Cretaceous 
(? Aptian) ; Western Australia. 

Gonyaulacysta margaritifera (Cookson & Eisenack 1960a). Upper Cretaceous 
(Senonian) ; Western Australia. 

Gonyaulacysta microceras (Eisenack 1958). Lower Cretaceous (Aptian) ; Germany. 

Gonyaulacysta millioudi (Sarjeant 19636, 1965). Upper Jurassic (Oxfordian) ; 
Switzerland. 

Gonyaulacysta muderongensis (Cookson & Eisenack 1958). Lower Cretaceous 
(Aptian) ; Western Australia. 

Gonyaulacysta obscura (Lejeune-Carpentier 1946). Upper Cretaceous ; Belgium. 

Gonyaulacysta pachydermia (Deflandre 1938). Upper Jurassic (Oxfordian) ; 
France. 

Gonyaulacysta per j or ans (Cookson & Eisenack 1958). Upper Jurassic ; Papua. 

Gonyaulacysta scarburghensis Sarjeant 19646 (= Gonyaulax areolata n.n. Sarjeant 
1961). Upper Jurassic (Oxfordian) ; England. 

Gonyaulacysta scotti (Cookson & Eisenack 1958). Upper Jurassic ; Western 
Australia. 

Gonyaulacysta serrata (Cookson & Eisenack 1958). Upper Jurassic-? Lower 
Cretaceous ; Papua. 

Gonyaulacysta tenuicer as (Eisenack 1958). Lower Cretaceous (Aptian) ; Germany. 

Gonyaulacysta wetzeli (Lejeune-Carpentier 1939). Upper Cretaceous ; Belgium. 

The following described species are doubtfully included in Gonyaulacysta on the 
basis of general structure but in absence of clear knowledge of the mode of archaeo- 
pyle formation. 

} Gonyaulacysta aceras (Eisenack 1958). Lower Cretaceous (Aptian) ; Germany. 

? "Gonyaulacysta cornigera (Valensi 1953). Middle Jurassic (Bathenian) ; France. 

1 Gonyaulacysta freakei (Sarjeant 19636). Upper Jurassic (Oxfordian) ; England. 

} Gonyaulacysta longicornis (Downie 1957). Upper Jurassic (Kimmeridgian) ; 
England. 

} Gonyaulacysta mamillifera (Deflandre 1939). Upper Jurassic (Kimmeridgian) ; 
France. 



13^ MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

IGonyaulacysta nannotrix (Deflandre 1939). Upper Jurassic (Kimmeridgian) ; 
France. 

IGonyaulacysta nealei (Sarjeant 1962ft). Upper Jurassic (Oxfordian) ; England. 

tGonyaulacysta nuciformis (Deflandre 1938). Upper Jurassic (Oxfordian) ; 
France. 

IGonyaulacysta porosa (Lejeune-Carpentier 1946). Upper Cretaceous ; Belgium. 

?Gonyaulacysta transparens (Sarjeant 1959). Middle Jurassic (Callovian) ; 
England. 



Genus ACANTHOGONYA ULAX nov. 

Derivation of name. Greek, akantha, thorn, prickle ; a spiny variant of the 
Gonyaulax tabulation type. 

Diagnosis. Proximate dinoflagellate cysts, spherical, ellipsoidal, ovoidal or 
polyhedral, with the tabulation 3-4', o-ia, 6", 6g, 6'", ip, 0-1 p. v., 1"". Cingulum 
strongly or weakly helicoid ; sulcus generally or constantly extending on to epitract. 
Apical horn present only infrequently ; median and antapical horns lacking. 
Sutures in form of low ridges bearing rows of spines, simple or furcate, or distinguish- 
able only as rows of spines. Shell bearing general cover of simple or furcate spines, 
identical to or differing from those on sutures ; spines fewer or totally lacking on 
cingulum and/or sulcus. Length of spines always less than \ of shell width. Surface 
smooth, granular, nodose, punctate or reticulate. Precingular archaeopyle formed 
by loss of plate 3". 

Type species. Gonyaulax venusta Klement i960. Upper Jurassic (Oxfordian to 
Kimmeridgian) ; Germany. 

Remarks. There are a group of Upper Jurassic species characterized by posses- 
sion of a dense spine cover, through which a tabulation of Gonyaulax type may be 
determined with varying degrees of difficulty. It is probable that these forms 
developed into spinous species without tabulation. These species form a coherent 
group which are considered to merit a separate generic name. Gonyaulax venusta is 
selected as type-species, since it shows the tabulation most clearly. 

Forms of Gonyaulacysta with a coarsely tubercular surface, such as G. aculeata 
(Klement i960) may represent a transitional stage to Acanthogonyaulax. 

The following species accord with the diagnosis of this genus : 

Acanthogonyaulax acanthosphaera (Sarjeant 1961) comb, nov., Upper Jurassic 
(Oxfordian) ; England. 

A . paliuros (Sarjeant 1962a) comb. nov. Upper Jurassic (Oxfordian) ; England. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 133 

Genus HESLERTONIA nov. 

Derivation of name. Based on the name West Heslerton, Yorkshire, from 
which the type species was first described. 

Diagnosis. Chorate dinoflagellate cysts, spherical, ellipsoidal, ovoidal or poly- 
hedral, with high sutural crests outlining the tabulation 3-4', o-ia, 6", 6g, 6'", ip, 
0-1 p. v., 1"". Cingulum strongly or weakly helicoid ; sulcus generally but not 
constantly extending on to epitract. Apical and antapical horns absent. Sutures 
perforate or imperforate ; their distal edges smooth or denticulate. Crest height 
exceeds \ of shell width. Surface smooth, granular, punctate, nodose or reticulate. 
Precingular archaeopyle formed by loss of plate 3" ; archaeopyle sometimes absent. 

Type species. Gonyaulax heslertonense Neale & Sarjeant 1962. Lower Cretace- 
ous (Hauterivian) ; England. 

Remarks. This genus is a chorate equivalent of Gonyaulacysta, characterized by 
its disproportionately high crests. 



Heslertonia heslertonensis (Neale & Sarjeant) 
1962. Gonyaulax heslertonense Neale & Sarjeant : 440, pi. 19, fig. 5, pi. 20, fig. 5 ; text-fig. 1. 

Remarks. Forms closely comparable to this species have been figured and 
described from the Middle Cretaceous of Australia as Cymatiosphaera striata Eisenack 
& Cookson (i960 : 9, pi. 3, figs. 10, 11). Both forms have in common high, striate 
crests : the figures suggest that the Australian species also has a cingulum and a 
determinable tabulation. A full restudy of the Australian specimens appears neces- 
sary to determine whether H. heslertonense and C. striata are congeneric or conspecific ; 
should the latter prove to be the case, the earlier name striata would have priority. 



Genus LEPTODINIUM Element i960 : 45 

Emended diagnosis. Proximate dinoflagellate cysts, spherical, ovoidal, ellip- 
soidal or polyhedral, with the tabulation 4', 6", 5-?6g, 5'", ip, 1"". Cingulum 
strongly or weakly helicoid, sulcus generally but not constantly extending on to 
epitract, undivided or subdivided into a pattern of ventral plates. Sutures between 
plates in form of low ridges, or bearing crests of varied form (smooth, denticulate or 
spinous ; perforate or imperforate). Height of crests always less than \ of shell 
width. Surface of shell smooth, granular or punctate. Precingular archaeopyle 
formed by loss of plate 3" ; not all individuals may show an archaeopyle. 

Type species. Leptodinium subtile Klement i960. Upper Jurassic (Oxfordian 
to Lower Kimmeridgian) ; Germany. 



134 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Remarks. The diagnosis is emended to include mention of the archaeopyle and 
more detail of other features. Differentiating features from Gonyaulacysta 
are the smaller number of postcingular plates and the lack of an anterior intercalary 
plate. A number of species of the latter genus show reduction of the first post- 
cingular plate : presence or absence of an anterior intercalary plate is then determin- 
ative. 



Leptodinium alectrolophum sp. no v. 

PL 15, figs. 3-6 ; Text-fig. 34 

Derivation of name. Greek, alectrolophos, cockscomb, in reference to the 
distinctive crests. 

Diagnosis. A Leptodinium having an ovoidal theca, without apical horn. 
Tabulation 4', 6", 7c, 5'", ip, 1"" ; plate boundaries bearing high, delicate crests 
which form slight projections at their points of junction. Sulcus and cingulum both 
of moderate breadth : sulcus relatively long, extending almost from apex to antapex. 
Cingular plate 7c roughly diamond-shaped. Apical prominence formed by junction 
of crests of apical plates. 

Holotype. B.M.(N.H.) slide ¥.51725(1). Speeton Clay, Shell West Heslerton 
Borehole No. I., West Heslerton, Yorks., at 39 metres depth. Lower Cretaceous 
(Middle Barremian). 

Paratype. ¥.51725(2). Same locality and horizon. 

Dimensions. Holotype : overall length 56^, breadth 50[x ; shell length 47-511, 
breadth 42-5(x ; width of cingulum 0.5- 5p.. Paratype : overall length 6i-$\i, breadth 
54- 5(j. ; shell length 50[x, breadth 46^ ; width of cingulum c.6(jl. Other specimens 
observed were of intermediate dimensions. 





Fig. 34. Leptodinium alectrolophum sp. nov. Tabulation. Left, oblique dorsal 
view ; right, oblique ventral view. x c. 800. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 135 

Description. Theca ovoidal, an appearance of polygonality being imparted by 
the crests. The pericoel surface bears a coarse granulation, granules being rather 
regularly spaced. The crests are thin and high, with minute, inconspicuous perfo- 
rations. Their distal edge is usually smooth, occasionally finely denticulate ; 
crests of a single individual may in part have smooth, in part denticulate, edges. 

The apical prominence appears to be formed solely by the junction of crests 
bounding the four apical plates ; there appears to be no apical horn as such. Apical 
plate 1' occupies the anterior extension of the sulcus ; since the sulcus is long and 
approaches the apex, plate 1' is proportionately small. The six precingular plates 
are all quite large. Presence of an anterior intercalary plate was suspected but not 
confirmed ; if present, this plate is relatively small. Five well-developed post- 
cingular plates are present ; plate 1'" is reduced to accommodate a quadrate 
posterior intercalary plate. The antapex is occupied by a single, large plate. 

The cingulum forms a strong laevorotatory spiral such that its two ends differ in 
antero-posterior position by roughly twice its width. There are six clear cingular 
plates, plus a seventh, diamond-shaped plate, here designated 7c, which lies between 
the posterior end of the cingulum and the sulcus. The sulcus is narrow and long, 
extending almost from apex to antapex. 

An archaeopyle is not present in the holotype ; however, the paratype has a 
well-developed precingular archaeopyle formed by loss of plate 3". 

Remarks. Leptodinium alectrolophum differs from all described species in its 
combination of crest and thecal morphology and tabulation. It resembles Gonyau- 
lacysta gongylos in having a seventh polygonal plate at the posterior end of the cingu- 
lum, but differs in tabulation and crest form and shape. Heslertonia heslertonense 
has even higher crests ; the surface lacks similar granulation and the tabulation is 
again different. 

In certain orientations, the high crests of this species produce a misleading 
resemblance to Scriniodinium : however, detailed study shows that no pericoel is 
present. 

The form from the Aptian of Germany, figured by Eisenack (1958, pi. 22, fig. 4) as 
7Gonyaulax sp., may well be attributable to this species. 

Presence of only five postcingular plates presumably results from the trend of 
reduction of plate 1'" ; thus plate 1'" of Leptodinium corresponds to plate 2'" of 
Gonyaulacysta. 

other species 

The following species are retained in this genus and accord with the emended 
diagnosis : 

Leptodinium arcuatum Klement i960. Upper Jurassic (Upper Oxfordian); 
Germany. 

Leptodinium maculatum Cookson & Eisenack 19616. Eocene ; Rottnest Island, 
Western Australia. 



136 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Leptodinium membranigerum Gerlach 1961. Oligocene ; Germany. 

Leptodinium mirabile Klement 1960. Upper Jurassic (?Oxfordian-Lower 
Kimmeridgian) ; Germany. 

? Leptodinium tenuicornutum Cookson & Eisenack 1962&. Cretaceous (PAlbian) ; 
Western Australia. 



Genus RAPHIDODINIUM Deflandre 1936 : 184 

Type species. Raphidodinhim fucatuni Deflandre 1936. Upper Cretaceous ; 
France. 

Remarks. This genus comprises highly condensed proximo-chorate cysts of 
ovoidal shape, characterized by possession of a very few extremely long spines, 
about 12 in number and up to twice the shell length. The shell surface bears low 
crests outlining a tabulation : the spines arise from crest nodes. The tabulation 
has not been determined, nor has an archaeopyle been reported ; the systematic 
position thus remains obscure. It is clearly a cyst genus, however, since spines 
arise from the cingulum. 



Genus PSALIGONYA ULAX nov. 

Derivation of name. Greek, psalis, low building with a vaulted roof ; a 
variant of the Gonyaulax tabulation type with terminal pericoels. 

Diagnosis. Bicavate dinoflagellate cysts, pericoel separated into two portions by 
broad median zone of contact with inner body. Outline spheroidal to ellipsoidal or 
subpolygonal with apical horn. Tabulation 3-4', ia, 6", 6c, 6'", ip, 1"" determinable 
on periphragm, sutures in form of ridges of varied height and ornament. No spines 
arise from crest nodes. Surface of endophragm and periphragm smooth, granular, 
nodose, reticulate or punctate. Precingular archaeopyle formed by loss of plate 3". 

Type species. Psaligonyaulax deflandrei sp. nov. Upper Cretaceous (Ceno- 
manian) ; England. 

Remarks. This new genus is distinguished from Gonyaulacysta by the presence 
of apical and antapical pericoels ; the species Gonyaulacysta cassidata, which has a 
closely similar tabulation pattern to that of the type species of Psaligonyaulax and 
which has an apical pericoel but no antapical pericoel, may well represent an inter- 
mediate form. 

Psaligonyaulax is distinguished from Scriniodinium sensu stricto by the separation 
of the pericoel into two parts ; from the subgenus Scriniodinium by the presence of a 
clear tabulation ; from the subgenus Endoscrinium by possession of a posterior 
intercalary plate and an antapical plate. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



137 



Psaligonyaulax deflandrei sp. nov. 
PL 14, figs. 7, 8 ; Text-fig. 35 

1964. Gonyaulax cassidata Eisenack & Cookson ; Cookson & Hughes : 42, pi. 5, fig. 11 only. 

Derivation of name. Named in honour of Professor Georges Deflandre, who has 
published fundamental studies of dinoflagellates in the French Upper Cretaceous 
between 1932 and the present. 

Diagnosis. A Psaligonyaulax having a spindle-shaped outline, truncated 
posteriorly, with ovoidal inner body. Apical pericoel surmounted by bifid horn, 
antapical pericoel flattened. Tabulation 4', ia, 6", 6c, 6'", ip, 1"". Crests of moder- 
ate height with smooth or denticulate edges. Cingulum broad, strongly spiral : 
sulcus narrower but widening posteriorly. Surfaces of endophragm and periphragm 
smooth or only minutely granular : an irregular scatter of tubercles may be present 
on periphragm. 

Holotype. Geol. Surv. Colin, slide PF.3049(i). Chalk, H.M. Geological Survey 
Borehole, Fetcham Mill, Surrey, at 730 feet depth. Upper Cretaceous (Cenomanian) . 

Dimensions. Holotype : overall length 75[x, breadth 44^ ; length of inner body 
35 \i, breadth 40[x. Range of dimensions : overall lengths 72 to 82 ;x, breadths 43 to 
6o[x. 





Fig. 35. Psaligonyaulax deflandrei sp. nov. Tabulation. Left, ventral view ; 
right, dorsal view (plate 3" is missing). x c. 1000. 



138 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. The apical horn is more or less conical, a bifid appearance being 
imparted by the apical junction of crests separating the four apical plates. Plate i' 
is narrow and elongate, occupying the anterior prolongation of the sulcus ; the 
anterior intercalary plate is also rather elongate. Six precingular and six post- 
cingular plates are present : plate i'" is very reduced and elongate. A posterior 
intercalary plate separates plates i'" and 2'" from the single plate occupying the 
antapex. 

The cingulum forms a laevorotatory spiral such that its two ends differ in antero- 
posterior position by three times its width : six cingular plates are present. The 
sulcus is constricted in its median portion, but widens considerably as it approaches 
the antapex. 

The crests are in part smooth, in part denticulate : they are sometimes very 
finely perforate. A scatter of tubercles may be present, their number and distribu- 
tion varying considerably between individuals. 

Plate 3" is consistently lost in archaeopyle formation : its absence is not always 
obvious in unstained specimens, as a result of the delicacy and tranparency of the 
shell. 

Remarks. Psaligonyaulax deflandrei sp. nov. is present throughout the Ceno- 
manian of the Fetcham Mill Borehole, but it is never abundant. Cookson & Hughes 
(1964) figured a representative of this species from the Cambridge Greensand 
(PAlbian-Cenomanian) as Gonyaulax cassidata. The latter species, now Gonyau- 
laesyta cassidata, has a comparable distribution and a similar tabulation : it may be 
related to P. deflandrei, but intermediate forms are not known. 

OTHER SPECIES 

The species Scriniodinium apaletum Cookson & Eisenack i960, from the Upper 
Jurassic of Australia and Papua, appears attributable to Psaligonyaulax : its 
tabulation has not, however, been described to date. 

Following the reconsideration herein of the genera Hystrichosphaeropsis and 
Rottnestia, the species R. simplicia Cookson & Eisenack 19616, which has poorly 
developed apical and antapical pericoels and lacks spines arising from crest nodes, 
becomes Psaligonyaulax simplicia (Tertiary ; Rottnest Island, Australia). 

Genus HYSTRICHOSPHAEROPSIS Deflandre 1935 

Emended diagnosis. Bicavate dinoflagellate cysts, pericoel divided by broad 
median zone of contact with inner body. Outline typically somewhat angular, 
apical and antapical periocoels typically quadrate in outline ; apical horn arising 
from former. Tabulation ?3-4', ?ia, 6", 6c, 6'", ip, 1"", determinable on periphragm ; 
sutures in form of ridges of varied height and ornamentation ; simple or furcate 
spines of varied length arising from some or all crest nodes. Surface of endophragm 
and periphragm smooth, granular, punctate, nodose or reticulate. Precingular 
archaeopyle formed by loss of plate 3". 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 139 

Type species. Hystrichosphaeropsis ovum Deflandre 1935. Upper Cretaceous ; 
France. 

Remarks. The name Hystrichosphaeropsis was originally proposed as a separate 
genus, but was later relegated to the status of a subgenus of Hystrichosphaera 
(Deflandre 19366). Its status as a separate genus was implicitly revived by the 
inclusion of this name in a list of valid genera by Eisenack (1963a : 118). 

The generic name Rottnestia was subsequently proposed by Cookson & Eisenack 
(1961b : 40-42). Deflandre, in a letter to the author (written in 1963 and here 
quoted by permission) comments as follows : 

" Le genre Rottnestia Cookson et Eisenack 1961 est synonyme du genre Hystri- 
chosphaeropsis Defl. 1935 (subgen. in Defl. 1937). Le type (H. borussica Eisenack) 
est tout a fait sembable a H. ovum Defl. 1935. Les autres especes d' Hystricho- 
sphaeropsis sont H. simplicia (C. et E.) et H. wetzeli ; Defl. 1935. " 

On this basis, it appears necessary that the generic name Rottnestia should be 
abandoned. The revised diagnosis of Hystrichosphaeropsis, here formulated, 
incorporates in general the diagnostic features quoted in both earlier diagnoses (i.e. of 
Hystrichosphaeropsis and Rottnestia) ; but forms lacking nodal processes are excluded 
and attributed to the new genus Psaligonyaulax. The author was courteously 
permitted by Prof. Deflandre to examine the type species during a visit to Paris in 
1961 ; the tabulation was elucidated to be as here quoted. The figures of Rottnestia 
suggest the same tabulation. 

other species 

Although Prof. Deflandre considers Rottnestia borussica to be probably conspecific 
with Hystrichosphaeropsis ovum, this remains to be confirmed : the former species is 
thus provisionally retained as Hystrichosphaeropsis borussica (Tertiary ; Rottnest 
Island, Australia). 

Hystrichophaeropsis wetzeli Deflandre 1935 (Upper Cretaceous ; France) accords 
with the revised diagnosis. 



Genus CARPODINIUM Cookson & Eisenack 19626 : 489 

Type species. C. granulatum Cookson & Eisenack 1962b. Lower Cretaceous 
(Aptian-Albian) ; Australia. 

Remarks. This genus was diagnosed in the following terms (19626 : 489) : 

" Shell elongate — oval to ellipsoidal, divided almost equally by an equatorial 
girdle. Epitheca with a distinct horn, hypotheca devoid of horns or projections. 
Pre- and post-equatorial plates probably six in number, elongate trapezoidal 
and bordered with wings. The longitudinal furrow broadens gradually from 
the apex to the antapex. A pylome develops on the dorsal surface of the epi- 
theca. " 



i 4 o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

In absence of full knowledge of the tabulation, the above diagnosis includes no 
characters, save possibly the posterior widening of the sulcus, which distinguish it 
from Gonyaulax, as accepted at the time of publication, or from Gonyaulacysta as 
defined by Deflandre and here redefined. The status of this genus must be regarded 
as questionable. 



[Genus RHYNCHODINIOPSIS Deflandre 1935] 

Type species. Rhynchodiniopsis aptiana Deflandre 1935. Lower Cretaceous 
(Aptian) ; France. 

Remarks. In his first full description of this genus (1936a : 32), Deflandre 
remarks on its apparent close relationship to Gonyaulax. Examination of his 
excellent figures suggests the tabulation 4~?5', ?ia, 6", 6g, 6'", ip, 1"" ; a pre- 
cingular archaeopyle is present, formed by loss of plate 3". Three distinguishing 
characteristics are cited by Deflandre — the presence of a strong, hollow, apical horn ; 
the presence of denticulate, aliform crests on sutures ; and the presence of strong 
curved spines arising from crest nodes along the edges of the cingulum. The first 
two characters are shared by many species of Gonyaulacysta ; the figures indeed 
strongly suggest a close affinity to Gonyaulacysta jurassica. The third distinguishing 
character does not alone warrant separation to generic level. 

It is considered that this genus was, at the time of its publication, effectively a 
junior homonym of Gonyaulax, none of the characters cited warranting the creation 
of a new name. It is therefore proposed that the name Rhynchodiniopsis be aband- 
oned and the single species, R. aptiana, from the Lower Cretaceous (Aptian) of 
France, be transferred to Gonyaulacysta. 



Genus HYSTRICHODINIUM Deflandre 1935 : 229 

Emended diagnosis. Proximo-chorate dinoflagellate cysts, spheroidal, ovoidal 
or polygonal in shape. Tabulation in general accord with Gonyaulax pattern, but 
not determined in detail. Long, hollow spines, rounded in cross-section and fairly 
stiff, arising from positions of plate boundaries : plate boundaries otherwise marked 
by low crests or not at all. Cingulum strongly or weakly helicoid, well-marked ; 
sulcus poorly marked. Length of spines variable, but typically exceeding \ of shell 
width. Shell surface smooth, granular, punctate, nodose or areolate. A precingular 
archaeopyle formed, presumably by loss of plate 3". 

Type species. Hystrichodinium pulchrum Deflandre 1935. Upper Cretaceous ; 
France. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 141 

Remarks. The generic diagnosis is emended to include reference to mode of 
archaeopyle formation and to specify the correspondence of spine position to sutures. 
This revision follows the examination of specimens of the type species preserved in 
flint (see below). The genus as now redefined differs from Gonyaulacysta in the height 
of sutural spines ; from Xiphophoridium in mode of archaeopyle formation ; and 
from Heliodinium in the rounded, not flattened, nature of the spines and the less 
well-marked sutures. 

Hystrichodinium pulchrum Deflandre 

PL 16, figs. 7, 8 

1935. Hystrichodinium pulchrum Deflandre : 229, pi. 5, fig. 1 ; text-figs. 9-1 1. 
1936a. Hystrichodinium pulchrum Deflandre ; Deflandre : 58, text-fig. 101. 
1936b. Hystrichodinium pulchrum Deflandre ; Deflandre : 34, pi. 8, figs. 3-8, pi. 9, fig. 3. 
1 941. Dinoflagellate W. Wetzel, O. Wetzel & Deflandre, text-fig. 7. 



1944. Hystrichodinium pulchrum Deflandre 
1952a. Hystrichodinium pulchrum Deflandre 
19526. Hystrichodinium pulchrum Deflandre 
1955. Hystrichodinium pulchrum Deflandre 
1959. Hystrichodinium pulchrum Deflandre 
1961. Hystrichodinium pulchrum Deflandre 
1963. Hystrichodinium pulchrum Deflandre 



de Wit, unnumbered text-fig. 

Deflandre, text-fig. 103. 

Deflandre, text-fig. 300B. 

Valensi : 591, pi. 3, fig. 11. 

Gocht : 58, pi. 3, figs. 11a, b, pi. 5. fig. 7. 

Alberti : 14, pi. 8, figs. 6-10. 

Gorka : 32, pi. 5, fig. 5. 



Material (Figured). B.M.(N.H.) slide V.13937 (1, 2). Flint from the Chalk 
(no locality or horizon). 

Dimensions. Figured specimens : No. 1 : overall length I02[i, breadth 98^, 
shell length 55^, breadth 44^. No. 2 : overall length ii5(x, breadth 8o;i. ; shell 
length 55fi, breadth 35^. Observed range ; overall lengths i02-H5(x, breadths 
8o-ioi(a. 

Remarks. This species has long been known from the Upper Cretaceous flints, 
although its structure has not yet been fully determined. It appears to be synony- 
mous with the species described by White (1842 : pi. 4 div. 3 fig. 6 ; 1844, pi. 8, 
fig. 5) and by Wilkinson (1846, pi. 8, figs. 2-3) as Xanthidium spinosum ; this species 
was subsequently transferred to Hystrichosphaeridium by Deflandre (1937a : 31) and 
to Baltisphaeridium by Downie & Sarjeant (1963 : 92) on taxonomic grounds, but 
has never been redescribed. Prolonged enquiry by the present author among the 
universities, libraries and museums of Britain indicates that the holotypes of White 
and Wilkinson are lost ; since Hystrichodinium pulchrum is well-defined and a name 
in widespread use, it is proposed that the earlier name spinosum be abandoned. 

The above enquiry brought to light a number of unlocalized flint slides, in each 
case of unspecified source, which contain specimens of " xanthidia ", including a 
number of examples of Hystrichodinium pulchrum. Examination of these indicated 
the precingular character of the pylome and that the distribution of spines corres- 
ponds to the positions of sutures, necessitating revision of the generic diagnosis. A 
full restudy and redescription of this species, based on material extracted by chemical 
techniques, is clearly necessary. 



i 4 ^ MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

OTHER SPECIES 

The following species are here attributed to the genus Hystrichodinium and accord 
with the revised diagnosis : 

Hystrichodinium compactum Alberti 1961. Lower Cretaceous (Valanginian) ; 

Germany. 
Hystrichodinium furcatum Alberti 1961. Lower Cretaceous (Hauterivian) ; 

Germany. 

Hystrichodinium oligacanthum Deflandre & Cookson 1955. Lower Cretaceous ; 
Australia. 

Hystrichodinium ramoides Alberti 1961. Lower Cretaceous (Barremian) ; Ger- 
many. 

The two remaining species previously attributed to this genus are considered only 
doubtfully referable to the revised genus. ? Hystrichodinium amphiacanthum 
Cookson & Eisenack 1958, has appendages which are polar in position and may 
warrant erection as a new genus. ?//. parvum Alberti 1961, from the Lower Creta- 
ceous (Aptian) of Germany, remains of uncertain generic allocation and merits a full 
restudy. 

Genus HELIODINIUM Alberti 1961 : 33 

Emended diagnosis. Proximo-chorate dinoflagellate cysts, spheroidal, ovoidal 
or subpolygonal in shape, with tabulation ?3', ?oa, 6", ?oc, 6'", Pop, 1"". Sutures 
faintly marked by ridges or low crests, from which arise flattened, dagger to ribbon- 
like, very flexible processes ; processes typically simple, bifurcate or multi-furcate. 
Cingulum strongly or weakly helicoid, bounded by low crests : sulcus less well 
marked. Shell surface smooth, granular or punctate. Precingular archaeopyle 
formed by loss of plate 3". 

Type species. Heliodiniumvoigti Alberti 196 1. Lower Cretaceous (Barremian) ; 
Germany. 

Remarks. The generic diagnosis is emended to incorporate fuller reference to the 
tabulation and to include reference to the mode of archaeopyle formation. Helio- 
dinium is distinguished from Hystrichodinium on the character of its processes. 

Heliodinium voigti Alberti 
PI. 16, fig. 2 ; Text-fig. 36 
1961. Heliodinium voigti Alberti : 33, pi. 8, figs. 1-5. 

Emended diagnosis. A Heliodinium having a subpolygonal shell, epitract 
almost conical and hypotract in form of truncated cone. Tabulation ?3', ?oa, 6", 
?oc, 6'", Pop, 1"" ; sutures generally marked only by low ridges, but cingulum and 
antapex bordered by low crests. Processes dagger-like, frequently highly folded, 
length less than half shell length ; distal ends of processes typically simple, rarely 
bifurcate or trifurcate. Shell surface smooth or only minutely granular. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



143 



Holotype. Preparation No. A26, Geologisches Institut der Universitat, Tubing- 
en, Germany. Lower Cretaceous (Upper Barremian) ; Haverlahwiese, Germany. 

Material (figured). Geol. Surv. Colin, slide PF.3035(4). Chalk, H. M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous 
(basal Cenomanian). 

Dimensions. Holotype : shell length 48^1, breadth 38jx, length of processes 
i6-22[jl. Range of German specimens : shell length 48-60^, breadth 38-56^, 
length of processes i6-36fi.. Specimen here figured : overall length c.12$\l, breadth 
c.io5[x : shell length 62fi,, breadth 45jx. 

Description. This species occurs in low numbers in the assemblages from the 
Chalk at 840 and 810 feet depth (basal Cenomanian) in the Fetcham Mill bore. 
Although a number of specimens were available for study, the majority proved 
unsuitable as a result of distortion or unfortunate orientation : the figured specimen 
was the only one capable of full study. It was thus not possible to confirm details 
of the apical structure. 

Plate 1' is elongate and corresponds to the apical prolongation of the sulcus. At 
least two other apical plates appear to be present : no anterior intercalary plate 
could be distinguished. Six precingular and six postcingular plates are present ; 
no posterior intercalary plate was distinguished. The antapex is occupied by a 
single plate. 

The cingulum forms a strong laevorotatory spiral whose two ends differ in antero- 
posterior position by three times its width. There appears to be no separation into 
cingular plates. The sulcus is narrow and extends to the antapex. 




Fig. 36. Heliodinium voigti Alberti. Tabulation. Left, ventral view ; 
right, dorsal view (plate 3" is missing). x c. 500. 



i )( MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 

The shell surface appears devoid of ornamentation. The processes are flattened 
and very flexible, generally simple — one process in the figured specimen is bifurcate, 
one trifurcate. 

Plate 3" is generally lost in pylome formation. 

Remarks. The diagnosis of this species is emended to incorporate new observa- 
tions. Alberti (1961 : 33) noted the presence of an archaeopyle in one specimen, 
but did not refer to this in the diagnosis. 

The stratigraphic range of the German specimens is Lower Barremian to ? Lower 
Aptian : the English occurrence thus represents a vertical extension of this range. 

Heliodinium patriciae Neale & Sarjeant 
PI. 16, fig. 1 

1961. Heliodinium patriciae Neale & Sarjeant : 451, pi. 19, fig. 3 ; text-fig. 7. 

Remarks. Re-examination of the holotype (B.M.(N.H.) slide V.51710), and 
other specimens, suggests a similar tabulation to that of H. voigti ; the mode of 
archaeopyle formation was not determined. In the original text fig. 7, the number 
of processes shown arising from the cingulum margins is now considered to be some- 
what exaggerated ; the figure is correct in all other particulars. 



B. Genera with apical archaeopyle 

Genus MEIO UROGONYA ULAX nov. 

Derivation of name. Greek, meiouros, curtailed, shortened ; a variant of the 
Gonyaulax tabulation type shortened by loss of the apex in archaeopyle formation. 

Diagnosis. Proximate dinoflagellate cysts, spherical, ellipsoidal, ovoidal or 
polyhedral, with the tabulation, 4', o-ia, 6", 6g, 5-6'", o-ip, 0-1 p. v., 1"". Cingu- 
lum strongly or weakly helicoid ; sulcus generally or constantly extending on to 
epitract. Sutures in form of low ridges or bearing crests of varied form (smooth, 
denticulate or spinous ; perforate or imperforate). Height of crests always less than 
I of shell width. Surface smooth, granular, nodose, punctate or reticulate. Arch- 
aeopyle formed by loss of apical plates, part of plate 1' sometimes left attached to 
shell ; not all individuals show an archaeopyle. 

Type species. Meiourogonyaulax valensii sp. nov., Middle Jurassic. 

Remarks. This genus presently contains a small group of Jurassic species ; 
unpublished data available to the author suggests the probability that a number of 
additional species will be described in the future from the Lower and Middle Jurassic. 

The apex has in no case been satisfactorily seen in position. The number of apical 
plates is deduced from the irregular profile of the archaeopyle and may be subject to 
future correction. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 145 

Meiourogonyaulax valensii sp. nov. 
PL 15, %• 7 ; Text-fig. 37 

1953. Gonyaulax sp. indet., Valensi : 27, pi. 2, figs. 12, 13. 

Derivation of name. Named after Lionel Valensi, who published the first full 
descriptions of Middle Jurassic dinoflagellate/acritarch assemblages. 

Diagnosis. A Meiourogonyaulax having a broadly ellipsoidal theca ; lacking 
apex in all specimens seen. Tabulation ?4', oa, 6", 6c, 6'", ip, 1 p. v., 1"". Crests of 
moderate height, slightly striated and irregularly perforate, with smooth or finely 
denticulate distal edges. Spines present at some crest nodes. Cingulum strongly 
spiral, relatively broad ; sulcus broadening posteriorly, subdivided by low ridges. 
Shell surface punctate or alveolar. 

Holotype. Specimen B.S.60 (L. Valensi preparation), Laboratoire de Micro- 
paleontologie, Ecole Pratique des Hautes Etudes, Paris. Chert from Airvault, 
Poitou, France. Middle Jurassic (Bathonian). 

Dimensions. Holotype : overall length 70^, breadth 70^1 ; shell length, approx. 
6o[jl, breadth approx. 50(1 ; width of transverse furrow c.6[x. 

Description. Although this species is based on Valensi's single specimen, the 
author has also seen a number of specimens in material from the Bathonian of the 
Aquitaine Basin, unfortunately not available for description. 




Fig. 37. Meiourogonyaulax valensii sp. nov. Tabulation. Left, ventral view 
right, dorsal view. X c. 1000. 



[46 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

From the angular profile of the apical archaeopyle, the former presence of at least 
four apical plates is deduced. There is no anterior intercalary plate. Six precingu- 
lar plates are present, plate 6" being slightly reduced. Six postcingular plates are 
present, plate 1'" being reduced and elongate, separated from the antapex by a 
moderately large posterior intercalary plate. The antapex is occupied by a single 
large plate and is separated from the sulcus by a quadrate posterior ventral plate. 

The cingulum forms a strong laevorotatory spiral such that its two ends differ in 
antero-posterior position by over twice its width. It is clearly subdivided into six 
cingular plates. The sulcus is roughly wedge-shaped, broadening towards the 
posterior ; it bears low ridges forming an irregular pattern. 

The shell surface is alveolar to punctate. The crests are moderately high, faintly 
striate and intermittently perforated ; their distal edges are in part smooth, in part 
finely denticulate. Crest nodes are strengthened by stout spines in some or all 
cases. The crests bordering the sulcus are very reduced. 

Remarks. Professor Georges Deflandre permitted the author and Mr. R. J. 
Davey to examine the holotype during visits to Paris, and also provided the photo- 
graph ; his courtesy is gratefully acknowledged. 

Meiourogonyaulax valensii sp. nov. is distinguished from the other species of this 
genus in the detail of tabulation and the nature of the crests. 

OTHER SPECIES 

The following species are here attributed to Meiourogonyaulax gen. nov. and accord 
with the diagnosis of this genus : 

Meiourogonyaulax bulloidea (Cookson & Eisenack 19606). Upper Jurassic 
(PTithonian) ; Western Australia. 

Meiourogonyaulax cristulata (Sarjeant 1959). Middle Jurassic (Callovian) ; 

England. 
A third species is doubtfully attributed to the genus : 

? Meiourogonyaulax caytonensis (Sarjeant 1959). Middle Jurassic (Callovian) ; 
England. 

The mode of archaeopyle formation in this latter species is not clear. The holotype 
has an intact apex, but lacks plate 2", suggesting a precingular archaeopyle in a 
unique position : other specimens lack an apex. Assignment to Meiourogonyaulax 
is thus provisional. 

Genus XIPHOPHORIDIUM nov. 

Derivation of name. Greek, xiphos, sword : phor-, suffix meaning to bear, 
carry. 

Diagnosis. Proximo-chorate dinoflagellate cysts, spheroidal to ovoidal or 
polygonal withtabulation ?4', ia, 6", o-ip, 6'", 1"". Cingulum strongly or weakly 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 147 

spiral, laevo-rotatory. Apical and antapical horns lacking. Sutures marked by 
high crests bearing long, dagger-like spines, broadly spaced ; crests bordering 
cingulum especially high and prominent. Surface smooth, granular, punctate or 
tuberculate. Archaeopyle formed by loss of apical plates ; not all individuals have 
an archaeopyle. 

Type species. Hystrichodinium alatum Cookson & Eisenack 19626. Cretaceous 
(PUpper Aptian-Cenomanian) ; Western Australia. 

Remarks. This genus comprises forms with high, pronouncedly spinose crests. 
It is distinguishable from Heliodinium, Hystrichodinium and Ctenidodinium by the 
mode of archaeopyle formation, from Heliodinium and Hystrichodinium also by the 
fact that the sutural spines arise from crests ; and from Ctenidodinium also by the 
fact that the cingulum is bordered on both sides by high crests. 



Xiphoridium alatum (Cookson & Eisenack) 
PL 16, fig. 11 

19626. Hystrichodinium alatum Cookson & Eisenack : 478, pi. 2, figs. 1-4. 

Emended diagnosis. A Xiphophoridium having an ovoidal to nearly globular 
shell, shell wall thin. Tabulation ?4', ia, 6", 6'", ?op, 1"" ; plates bounded by very 
high crests bearing long, dagger-like spines, crest curving inwards between bases of 
spines. Cingulum weakly spiral, of moderate breadth and bordered by especially 
high crests ; sulcus also of moderate breadth, extending to antapex. Shell surface 
not, or only minutely, granular, bearing numerous tubercles, sometimes apparently 
arranged to plate margins, generally without obvious arrangement. Apical archaeo- 
pyle present. 

Holotype. Specimen no. P. 21272, National Museum, Victoria, Australia. 

Material (figured). Geol. Surv. Colin, slide PF.305i(i). Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey, at 840 feet depth. Upper Cretaceous (basal 
Cenomanian). 

Dimensions. Holotype : overall length 125^, breadth 96^ : length of shell yo\i, 
breadth 52^. Range of Australian specimens : overall lengths ioo-i02[x, overall 
breadths 92-iooji.. As a result of orientation or preservation, it did not prove 
possible to obtain detailed measurements of the English specimens, but dimensions 
appear comparable. 

Description. This species occurs infrequently throughout the English Ceno- 
manian, some 20 specimens having been encountered. The specimen figured, seen 
in terminal view, was the best-preserved and allowed determination of the tabulation : 
all other specimens were damaged or distorted to some extent. It was not possible 
to prepare a satisfactory figure. 



148 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

The shape of the archaeopyle is that of a ragged polygon with a narrow sulcal 
notch, suggesting that four apical plates were originally present. Six precingular 
plates are present, plate 6" being reduced to accommodate a quadrate anterior inter- 
calary plate. Six postcingular plates are present ; no posterior intercalary plate 
could be distinguished in the specimens studied. The antapex is occupied by a 
single polygonal plate. 

The cingulum is weakly spiral, laevorotatory ; its structure was not clear in the 
English specimens, but the photographs of the Australian specimens suggest a 
division into cingular plates (?6). 

The crests are delicate, not or only minutely perforate : the spines arise simply as 
outgrowths of the crests and are somewhat flattened and dagger-like. The shell wall 
appears to lack ornament other than the tubercles. 

Remarks. In their original description of this species, Cookson & Eisenack 
noted the clear presence of tabulation and recognized this as a separating character 
from other species of Hystrichodinium, in which they then placed it. They do not 
record the presence of an apical archaeopyle but this feature is suggested in one of 
their figures (pi. 2, fig. 2). The diagnosis is here emended to include reference to the 
tabulation and the possession of an apical archaeopyle. 

Genus BELODINIUM Cookson & Eisenack 19606 : 249 

Type species. Belodinium dysculum Cookson & Eisenack 19606. Upper 
Jurassic (Tithonian) ; Australia. 

Remarks. This genus was diagnosed in the following terms : 

" Shell elongate, unequally divided by a circular girdle. Main body marked 
into fields by delicate ledges : epitheca with a hollow membraneous horn, 
hypotheca with a flattened membraneous expansion." 

In the absence of a full knowledge of the tabulation, distinction of this genus depends 
on the circular nature of the cingulum and the presence of an antapical pericoel. The 
description of the type species (Cookson & Eisenack 19606 : 250) makes it clear that 
archaeopyle formation is by loss of the apical plates. The authors state that their 
interpretation of the genus is " provisional " and " incomplete " : a fuller study of 
the genus and a revision of the diagnosis are clearly necessary before its status can be 
validly assessed. 

Genus MICRODINIUM Cookson & Eisenack 1960a : 6 

Emended diagnosis. Proximate dinoflagellate cysts, spheroidal to ovoidal in 
shape and usually small. Epitract smaller than hypotract. Tabulation 1', o-?ia, 
6", 6c, 6'", ip, 1"", with differentiation in some species of additional plates in ventra, 
region. Cingulum broad, weakly spiral ; sulcus broad, extending from apex to 
antapex. Sutures bearing crests in form of low ridges (perforate or imperforate), 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



149 



smooth, denticulate, or bearing spines of varying lengths ; alternatively sutures 
marked by lines of closely set spines. Shell surface smooth, granular, punctate or 
tuberculate. Archaeopyle formation by loss of single apical plate. 

Type species. Microdinium ornatum Cookson & Eisenack 1960a. ?U. Aptian- 
Turonian : Australia. 

Remarks. At the time when it was proposed, this genus was technically invalid, 
since its tabulation falls within the limits specified for Gonyaulax. However, 
Microdinium is now recognized to be a cyst genus and, regarded as such, becomes a 
valid entity, since its tabulation does not accord with that of Gonyaulacysta either in 
the original definition of Deflandre or as here emended. 

Representatives of this genus are relatively frequent in the English Cenomanian. 
The generic diagnosis is emended to accommodate variations in morphology exhibited 
by these forms. 

Microdinium differs from the majority of fossil dinoflagellate cysts in having an 
apical archaeopyle ; from Meiourogonyaulax and Xiphophoridium in having only a 
single apical plate ; and from Glyphanodinium in having six precingular plates. 



Microdinium cf. ornatum Cookson & Eisenack 
PL 16, figs. 3-6 ; Text-fig. 38 

1960a. Microdinium ornatum Cookson & Eisenack : 6, pi. 2, figs. 3-8, text-figs. 2-4. 

Material (Figured). Geol. Surv. Colin, slide PF.305o(i). Chalk, H.M. Geologi- 
cal Survey Borehole, Fetcham Mill, Surrey, at 670 feet depth. Upper Cretaceous 
(Upper Cenomanian). 

Dimensions. Figured specimen : length 40^, breadth 32^. Range length 
c.30-45fx, breadth c. 22-35^. 





Fig. 38. Microdinium cf. ornatum Cookson & Eisenack. Tabulation. Left, 
ventral view ; right, dorsal view (the apex is missing), x c. 1250. 



150 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Description. This form occurred in moderate abundance in the upper levels of 
the Cenomanian of the Fetcham Mill Borehole, over 20 specimens having been 
seen ; the apex was missing in all specimens seen. 

The shell is ovoidal in shape, with a somewhat flattened antapex and an apex 
truncated by the archaeopyle. Six precingular and six postcingular plates are 
present. The presence of an anterior intercalary plate was suggested in some 
specimens, but could not be confirmed as a result of distortion around the archaeopyle. 
Plates 1'" and 2'" are reduced to accommodate a large posterior intercalary plate ; 
this is of comparable size to the single antapical plate, some specimens indeed give 
the impression of having two antapical plates. 

The cingulum is very broad and not hollowed ; it is weakly spiral, laevorotatory, 
its two ends scarcely differing in antero- posterior position. The sulcus is broad 
throughout its length, but broadest as it approaches the antapex : ventral plates are 
absent. 

The shell surface is generally quite smooth, but bears a scatter of tubercles, some 
of which are aligned parallel to sutures ; the number and arrangement of tubercles 
varies between individuals. The sutures bear closely set spines, capitate and of 
constant length, giving almost the impression of perforate crests : in vertical view, 
these give the impression of a string of beads. 

Remarks. These English Cenomanian forms generally closely resemble Micro- 
dinium ornatum as described from Australia, but differ in two details — the absence of 
a plate separating the posterior end of the cingulum from the sulcus, and the form of 
the crests, which are constantly in the form of closely set spines. It is highly 
probable that they fall within the range of variation of M. ornatum, since they accord 
closely with the photographs and since Cookson & Eisenack state (p. 7) that " the 



?ia 





Fig. 39. Microdinium setosum sp. nov. Tabulation. Left, ventral view ; 
right, dorsal view, x c. 1250. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 151 

outer edge of the ledges may be missing " in some specimens ; it is also possible that 
representatives of two species have been placed together by those authors. For the 
present, it is considered appropriate that the English forms should be compared with, 
and not placed within, the species M. ornatum. 

Microdinium setosum sp. nov. 
PL 16, figs. 9, 10 ; Text-fig. 39 

Derivation of name. Latin, setosus, bristly ; referring to the spines on the 
sutures. 

Diagnosis. A Microdinium having an ovoidal shell with somewhat flattened 
antapex. The epitract considerably smaller than the hypotract ; a broad cingulum, 
weakly spiral, divides them. Tabulation ?i', oa, 6", 6c, 6'", ip, 1"" : two additional 
plates present in ventral region between two ends of cingulum. Sutures bearing low 
crests from which arise spines of moderate length, simple and well spaced ; shell 
surface minutely but densely granular. Apex characteristically lost in the pylome 
formation. 

Holotype. Geol. Surv. Colin, slide PF.3046(2). Chalk, H.M. Geological 
Survey Borehole, Fetcham Park, Surrey, at 840 feet depth. Upper Cretaceous 
(basal Cenomanian). 

Dimensions. Holotype : overall length 35^, breadth 30(1 ; shell length 33^, 
breadth 24^. Range of dimensions : overall lengths 33 to 38jx, breadths 24 to 37^. 

Description. This species is moderately abundant in the lower levels of the 
Cenomanian of the Fetcham Mill Borehole, over 30 specimens having been seen. The 
apex is presumed to have consisted of a single plate, but it was lost in the majority 
of specimens seen. In a few, the archaeopyle " lid " was still attached, but too 
buckled for its character to be determined. 

Six precingular and six postcingular plates are present, the former being consistent- 
ly smaller than the latter in the proportion that the epitract is smaller than the 
hypotract. Plates 1'" and 2'" are reduced : a posterior intercalary plate separates 
plate 2'" from the antapex. As in M. cf. ornatum, plate ip and the antapical plate 
are of comparable size and in some specimens look more like paired antapical plates. 

The cingulum is broad, not hollowed, and very weakly spiral, its two ends scarcely 
differing in antero-posterior position. It is divided into six cingular plates ; two 
ventral plates lie between its two ends and divide the sulcus into an epitractal and a 
hypotractal portion. 

The crests are low and bear simple, flexuous spines, the crest margin being scalloped 
between spine bases. The surface bears a uniform, dense cover of minute granules. 

Remarks. Microdinium setosum sp. nov. differs from M. ornatum in crest 
character, detail of tabulation, and granular surface. It is placed in Microdinium 
on the basis of general structure and apical archaeopyle : possession of only one apical 
plate was presumed but not confirmed. 



152 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Genus GLYPHANODINIUM Drugg 1964 

Type species. Glyphanodinium facetum Drugg 1964. Palaeocene (Danian) ; 
California, U.S.A. 

Remarks. This is a genus of distinctive proximate dinoflagellate cysts of pentago- 
nal shape, with the tabulation ?i', oa, 6c, 6'", ip, 1 p. v., 1"", the archaeopyle being 
formed by loss of the single (?) apical plate. The cingulum is situated high on the 
test, the epitract being thus small, the hypotract large. The overall shell size is 
small. It differs from Meiourogonyaulax in the apparent number of apical plates, 
and from Microdinium in overall shape and the presence of only five precingular 
plates. 

Genus EISENACKIA Deflandre & Cookson 1955 : 258 

1954. Eisenackia Deflandre & Cookson : 1236 (name only). 

Emended diagnosis. Proximate dinoflagellate cysts, spheroidal or ovoidal in 
shape, with the tabulation 2-3', 6", ?6c, 6'", 2p, 1"" ; additional plates occupy 
ventral area, there being no sulcus as such. Plates consisting of raised areas of shell 
surface, isolated frcm one another by pattern of " channels " corresponding in 
position to sutures. (It is here proposed that such inverse equivalents of sutures be 
termed " fossae ".) Cingulum weakly helicoid. Shell surface typically reticulate, 
possibly also granular or punctate. Apical archaeopyle formed by loss of apical 
plates. 

Type species. Eisenackia crassitabulata Deflandre & Cookson 1955. Paleocene 
to Lower Eocene ; Australia. 

Remarks. The diagnosis is emended to stress the characteristic form of the 
tabulation, as plates separated by fossae, and to include reference to the mode of 
archaeopyle formation. The latter character was remarked on by Deflandre & 
Cookson (1955 : 260) in the description of the type species. 

C. Genera with epitractal archaeopyle 
Genus RHAETOGONYA ULAX nov. 

Derivation of name. Refers to the occurrence of the type species in the Rhae- 
tian (Rhaetic) Stage, uppermost Triassic, and to possession of a Gonyaulax type of 
tabulation. 

Diagnosis. Proximate dinoflagellate cysts, spindle-shaped or biconical, typically 
with the tabulation 4', ia, 6", 6'", ip, 1"" : tabulation well or poorly marked by 
ridges or partially or entirely indeterminable. Cingulum strongly or weakly spiral, 
laevorotatory, divided into plates (?6c) or without such division. Surface smooth, 
granular, nodose, punctate or reticulate ; ornamentation may mask the tabulation. 
Archaeopyle (where present) epitractal, formed by schism of shell immediately 
anterior to cingulum. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 153 

Type species. Gonyaulax rhaetica Sarjeant, 1963a. Upper Triassic (Rhaetic) ; 
England. 

Remarks. This genus is created to accommodate the earliest known species 
having a tabulation of Gonyaulax type. The shape is unlike that of any other known 
fossil species having such a tabulation ; the plate boundaries are so poorly marked as 
to make it seem probable that any descendants would be non-tabulate. For these 
reasons, it is considered that a relationship with the species attributed to the genus 
Dichadogonyaulax gen. no v. is unlikely. Later genera having a spindle-shaped 
outline (Kalyptea ; Netrelytron) appear to consistently form precingular archaeopyles. 

OTHER SPECIES 

The following species also accords with the diagnosis of this genus and is here 
included in Rhaetogonyaulax accordingly : Rhaetogonyaulax chaloneri (Sarjeant 
1963a). Upper Triassic (Rhaetic) ; England. 

Genus DICHADOGONYAULAX nov. 

Derivation of name. Greek, dichados, half : refers to the almost median 
schism of the shell, so that typically half shells are encountered, and to the Gonyaulax 
— type tabulation. 

Diagnosis. Proximate dinoflagellate cysts, spheroidal, ovoidal, ellipsoidal or 
polyhedral, having the tabulation 3-5', o-?ia, 6", 5 6'", ip, 1"" : sulcus divided into 
plates or undivided, ventral region may show division into additional small plates. 
Cingulum strongly or weakly spiral, laevorotatory. Apical horn may be present ; 
median and antapical horns lacking. Sutures in form of low ridges bearing crests of 
varied form (smooth, denticulate or spinous ; perforate or imperforate) ; or marked 
by lines of spines. Archaeopyle (where present) epitractal, by schism of shell 
immediately anterior to cingulum. 

Type species. Gonyaulax culmula Norris 1965. Upper Jurassic (Portlandian) ; 
England. 

Remarks. Norris (1965) has described a group of species from the Portlandian 
which have in common their general morphology and mode of archaeopyle forma- 
tion, but whose tabulation accords sometimes to the Gonyaulax pattern, sometimes 
to that of Leptodinium. The tabulation of the type species, which lacks an anterior 
intercalary plate but possesses six postcingular plates, is indeed intermediate in 
character. On this basis, it is considered that common characters outweigh the small 
tabulation differences and that the diagnosis should embrace all forms with epitractal 
archaeopyles and generally similar morphology. 

other species 
The following species also accord with the diagnosis of this genus : 

Dichadogonyaulax pannea (Norris 1965) comb. nov. Upper Jurassic (Upper 
Kimmeridgian-Portlandian) ; England. 

D. schizoblata (Norris 1965) comb. nov. Upper Jurassic (Upper Portlandian) ; 
England. 



154 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

D. Genera with cingular archaeopyle 
Genus CTENIDODINIUM Deflandre 1938 : 181 

Emended diagnosis. Proximo-chorate dinoflagellate cysts, spheroidal, ovoidal, 
ellipsoidal or polygonal, having the tabulation 3-4', o-ia, 6", 6c, 6'", ip, 0-1 p. v., 
1"" ; sutures in form of low ridges bearing crests of varied form, typically but not 
constantly high and denticulate. Cingulum strongly or weakly spiral, laevo- 
rotatory ; suture on anterior margin of cingulum lacking crest, crest on posterior 
margin very high. Archaeopyle (where present) formed by schism along cingulum. 

Type species. Lithodinia jurassica var. omata Eisenack 1935. Middle Jurassic 
(Callovian) ; Germany. 

Remarks. The diagnosis is emended to include reference to tabulation and mode 
of archaeopyle formation ; the latter, in combination with the unequal crest develop- 
ment on either side of the cingulum, characterizes the genus. Both species currently 
attributable to the genus occur in the Middle to Upper Jurassic (Callovian to Oxfordi- 
an), the type species being known to range up into the Lower Oxfordian. 

other species 
The following species also accords with the revised diagnosis of the genus : 
Ctenidodinium tenellum Deflandre 1938. Upper Jurassic (Oxfordian) ; France. 

Genus WANAEA Cookson & Eisenack 1958 : 57 

Type species. Wanaea spectabilis Cookson & Eisenack 1958. Upper Jurassic ; 
New Guinea. 

Remarks. W. R. Evitt, in litt., has informed the writer that this genus comprises 
detached epitracts and hypotracts of a genus with a Gonyaulax-pa.ttem tabulation. 
High crests, perforated in varying degree to give a fringe-like appearance, border the 
cingulum : crests elsewhere on the shell are marked only by low ridges. Archaeopyle 
formation apparently results from schism along the cingulum, but the mechanism of 
the process appears more complicated than in Ctenidodinium. A full study of the 
genus is understood to be in press. 

E. Genera with archaeopyles formed by other means 

Genus PLURIARVALIUM Sarjeant 1962a : 260 

Type species. Pluriarvalium osmingtonense Sarjeant 1962a. Upper Jurassic 
(Upper Oxfordian) ; England. 

Pluriarvalium osmingtonense Sarjeant 
Text-fig. 40 
1962a. Pluriarvalium osmingtonense Sarjeant : 262, pi. 1, fig. 5 ; text-fig. 6. 

Remarks. This species is relatively abundant in certain horizons of the Upper 
Jurassic ; all specimens observed to date are either intact or severely damaged and 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



155 







Fig. 40. Pluriarvalium osmingtonense Sarjeant. Two damaged specimens, showing 
how the anterior portion of the ventral surface is apparently lost in archaeopyle forma- 
tion. Left, ventral view ; right, dorsal view, x c. 500. 



156 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

crumpled. Study of the damaged specimens suggests that archaeopyle formation 
may occur by loss of the anterior ventral surface (see Text-fig. 40) : such a method 
has not been observed in any other known dinoflagellate cyst. Further studies are 
needed before this suggestion can be confirmed ; but certainly, no specimens yet 
observed give suggestion of archaeopyle formation by more familiar methods. 

The holotype and paratypes of this species are in the collections of the Micro- 
palaeontology Laboratory, Department of Geology, University of Sheffield. 



CONCLUSIONS 

The characteristics and known stratigraphic distribution of the twenty-one valid 
genera here considered are summarized in the accompanying Table. At present, no 
coherent picture emerges regarding the stratigraphical distribution of the different 
archaeopyle types : fuller studies of critical intermediate assemblages are clearly 
necessary. All four principal modes of archaeopyle formation were operative by the 
Upper Jurassic and it seems likely that these represent four divergent lines of 
evolution. Rhaetogonyaulax may represent a trend towards non-tabulate cysts of 
spindle-shape ; Acanthogonyaulax towards non-tabulate, densely spinose forms ; 
and the ancestors of Hystrichosphaera may well be found in species of Gonyaulacysta 
with progressively lower crests bearing progressively higher spines. 

Dinoflagellate cysts basically having a Gonyaulax-type tabulation are shown to be 
dominant elements in Upper Jurassic and Lower Cretaceous assemblages, declining 
in importance (Hystrichosphaera excepted) in the Upper Cretaceous ; rare in the 
lowest Tertiary ; and apparently not represented after the Eocene. Their strati- 
graphic importance is thus greatest in the Upper Jurassic and Lower Cretaceous, 
where rapid evolution and limited vertical range combine to render many species 
satisfactory zonal indices. 



Table 4 









TABULATION 








FORM OF 
SUTURES 


TYPE OF 
ARCH AEO PYLE 


OTHER 
SPECIAL 
FEATURES 


OVERALL 
SHELL 
FORM 


KNOWN 

STRATIGRAPHIC 

RANGE 




GENUS 


< 


| 


5 2 


°" 


1 s 


| = 


c 0. 


Additional 

Plales 

llf present) 




Rhoetogonyoulax 


' 


1 


6 


6 


6 


1 


1 





LOW RIDGES OR 

INDETERMINABLE 


EPITRACTAL 


SPINDLE SHAPED 
SHELL 


PROXIMATE 


U. Triassic (Rhaelian) 




Gonyaulacysla 


3-4 


0-1 


6 


6 


6 


1 


1 


0-1 p.v. Ventral 
plates sometimes 
present 


CRESTS OR LINES 
OF SPINESIHEIGHT 
LESS THAN 1/4 
SHELL DIAMETER) 


PRECINGULAR 


APICAL HORN OFTEN 

PRESENT 


PROXIMATE 


M. Jurassic (Bajocian) to 
U. Cretaceous (Senonian) 




Meiourogonyaulax 


< 


0- 1 


6 


6 


5-6 


0- 1 




0- 1 p.v. 


LOW RIDGES 
OR CRESTS 


APICAL 





PROXIMATE 


M.-U. Jurassic 
(Balhonian-?Tilhon.an) 








Ctenidodinium 


3-4 


0-1 


6 


6 


6 


1 


1 


0-1 p.v. 


CRESTS 


CINGULAR 


HIGH CREST POSTERIOR 
TO CINGULUM: NO 
CREST ON ANTERIOR SIDE 


PROXIMO- 
CHORATE 


M.- U. Jurassic 
(Callovian - Oxfordian) 




Acanthogonyaulax 


3-4 


0- 1 


6 


6 


6 


1 


1 





LINES OF 
SPINES 


PRECINGULAR 


GENERAL SPINE COVER 


PROXIMATE 


U. Jurassic 

(Oxfordian- Kimmeridgian) 




Wonaeo 




Not determined in detail 




LOW RIDGES 
EXCEPT ALONGSIDE 
CINGULUM 


CINGULAR 


HIGH, FRINGE LIKE 

CRESTS BORDERING 

CINGULUM 


PROXIMO- 

CHORATE 


U. Jurassic 
(Oxfordian -Tithonian) 




Pluriorvolium 


?5 


2 


6 


?6 


6 


1 


1 


1 p.v., up to 7 
posterior circle 

plates 


LOW RIDGES 


? BY LOSS OF ANTERIOR 
VENTRAL SURFACE 





PROXIMATE 


U. Jurassic 
(U. Oxfordian) 




Leptodinium 


4 





6 


5-6 


5 


1 


1 





CRESTS OR LINES 
OF SPINES (HEIGHT 
LESS THAN 1/4 
SHELL DIAMETER) 


PRECINGULAR 




PROXIMATE 


U. Jurassic 
(Oxfordian)- Oligocene 








Belodinium 




Not determined in detail 


DELICATE CHESTS 


APICAL 


APICAL HORN 
ANTAPICAL PER1COEL 


PROXIMATE 


U. Jurassic 
(Tithonian) 








Dichadogonyoulax 


3-5 


0-?l 


6 


6 


5-6 


1 


1 


Ventral plates 
present 


CPESTS OR 
IINE5 OF SPINES 


EPITRACTAL 





PROXIMATE 


U. Jurassic 
( Partlandian) 




Heslertonia 


3-4 


0-1 


6 


6 


6 


1 


1 


0-1 p.v. 


VERY HIGH CREST5 
(GREATER THAN 
fa SHELL DIAMETER) 


PRECINGULAR 




CHORATE 


L.-U. Cretaceous 

( Hauterivian - Cenomanian) 










Heliodinium 


?3 


?0 


6 


?0 


6 


?0 


1 





DAGGER LIKE 
SPINES ARISING 
FROM LOW CRESTS 


PRECINGULAR 


SUTURAL SPINES 

FLAT, FLEXIBLE 


PROXIMO- 
CHORATE 


L.- U. Cretaceous 
(Hauterivian- Cenomanian) 








Hystriehodinium 




Not determined in detail 


LONG SPINES 
ARISING FROM 
POSITIONS OF 
SUTURES 


PRECINGULAR 


SUTURAL SPINES 
ROUNDED. STIFF 


PROXIMO- 
CHORATE 


L.-U. Cretaceous 
(Hauterivian -Senonian) 




Carpodinium 


? 


?6 


6 


? 


6 


9 








CRESTS 


PRECINGULAR 




PROXIMATE 


U. Cretaceous 
lAptian - Albion) 








Microdinium 


1 


0-?l 


6 


6 


6 


1 


1 


Ventral plates 

sometimes 

present 


LOW CRESTS OR 
LINES OF SPINES 


A PICAL 


EPITRACT SMALLER 
THAN HYPOTRACT 


PROXIMATE 


L.- U. Cretaceous 
(?U. Aptian-Turonian) 




Xiphophoridium 


?4 


1 


6 


?6 


6 


0-1 


1 





VERY HIGH CRESTS 
ESPECIALLY BORD- 
ERING CINGULUM 


AP ICAL 





PROXIMO- 
CHORATE 


L.-U. Cretaceous 
(?U. Aptian- Cenomanian 




Pioligonyoulox 


3-4 


1 


6 


6 


6 


1 


1 





CRESTS 


PRECINGULAR 


APICAL AND ANTAPICAL 
PERICOELS 


BICAVATE 


U. Cretaceous 
(Cenomanion)- Tertiary 




H ystrichosphaeropsis 


?3- 4 


?1 


6 


6 


6 


1 


1 





CRESTS WITH 
SPINES AT NODES 


PRECINGULAR 


APICAL AND ANTAPICAL 


BICAVATE 


U. Cretaceous (Tertiary) 




Raphidodinium 




Not determined in detail 


LOW, BEARING FEW 
VERY LONG SPINES 


NOT REPORTED 


SPINES STIFF UP TO 
TWICE SHELL LENGTH 


CHORATE 


U. Cretaceous 




Glyphonodinium 


?1 





5 


6 


6 


1 


1 


Ip.V. 


LOW CRESTS 


APICAL 


EPITRACT SMALLER 
THAN HYPOTRACT 


PROXIMATE 


Paleocene 




Eisenackia 


2-3 





6 


?6 


6 


2 


1 


Ventral plotes 

sometimes 
present 


FOSSAE 


APICAL 




PROXIMATE 


Paleocene - L. Eocene 











Characteristics and stratigraphical distribution of fossil Dinoflagellate 
cyst genera having a tabulation according with the Gonyaulax pattern. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 157 

VII. FOSSIL DINOFLAGELLATE CYSTS ATTRIBUTED TO B A LT I SPH AERI DI U M 

By R. J. DAVEY, C. DOWNIE, 
W. A. S. SARJEANT & G. L. WILLIAMS 

INTRODUCTION 

The genus Baltisphaeridium was proposed by Eisenack (1958 : 398) to accommo- 
date species of fossil microplankton having spherical to oval, nontabulate shells 
bearing simple or branching appendages, consistently closed distally. The type 
species selected was the Silurian species B. longispinosum, having a size range of 40 to 
75[x. Eisenack did not compare his new genus with the existing genus Micrhy- 
stridium Deflandre 1937 (defined as having a shell diameter inferior to 20[i.) : subse- 
quent workers, however, assumed a separation between the two genera on the basis 
of the size restriction of Micrhystridium. 

Staplin (196 1 : 408) proposed the redefinition of Micrhystridium by restricting it to 
forms having appendages closed distally and by removing the size restriction ; this 
redefinition made Baltisphaeridium into a junior synonym of Micrhystridium. 
This proposal was attacked by Eisenack (1962 : 96) and Downie & Sarjeant (1963 : 
83-84) ; the latter authors, while recognizing the arbitary nature of the upper size 
limit of Micrhystridium, nevertheless considered that this genus expressed a natural 
morphological grouping distinct from Baltisphaeridium. They proceeded to give 
an emended diagnosis for Baltisphaeridium, as follows : 

" Hystrichospheres with spherical to oval shells not divided into fields or plates, 
bearing + numerous processes, simple, branching or ramifying, hollow to solid, 
always with closed tips. The processes are not connected together distally and no 
outer shell, complete or incomplete, is present : the processes are most often of a 
single basic type, but processes of two or more types may be present. Mean and 
modal diameter of the shell greater than 20\l." 

At this date, separation of acritarchs from dinoflagellate cysts had not been made. 
Within the genus Baltisphaeridium, there were placed forms having pylomes ; 
forms with archaeopyles, variously situated ; and forms having no openings of any 
kind. Thus, within a single genus, there were classed together both species of 
demonstrable dinoflagellate affinity and morphologically similar forms of unproven 
and perhaps quite different affinity. 

An attempt is here made to remedy this confused situation. Species having 
spheroidal to ovoidal shells with apical archaeopyles, with the processes arranged so 
as to give a reflected tabulation 4', oa, 6", 6c, 6'", ip, 3"", are placed into the new 
genus Surculosphaeridium. Species having a spheroidal to ovoidal shell with an apical 
archaeopyle, but having numerous processes and an undetermined or intermediate 
tabulation, are placed in a second new genus, Cleistosphaeridium. Species having an 
elongate ovoidal to ellipsoidal shell, with an apical archaeopyle and processes arrang- 
ed into distinct rows, are placed in a third new genus Prolixosphaeridium. Species 
having a precingular archaeopyle are placed in a fourth new genus Exochosphaeridium. 
The residue of species, either with a circular pylome (such as the type species, B. 
longispinosum) or with no observed opening, are considered to be acritarchs and left 



158 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

within the genus Baltisphaeridium. A full restudy of this latter genus has recently 
been published by Staplin, Jansonius & Pocock (1965) ; a consideration of their 
revisions and proposals is outside the scope of the present paper. 

The Species hirsutum (Ehrenberg) and striolatum (Deflandre). 

Ehrenberg (1838) recorded the occurrence, in Cretaceous flints from Delitzsch, 
Saxony, of microplankton having simple, oval shells bearing a scatter of simple 
spines of moderate length. These he named " Xanthidium hirsutum (?) ", thus 
implying their identity with a modern Desmid, now designated Staurastrum hirsutum 
(Ehr.) Ralfs 1848. 

Reade (1839) illustrated under this name two quite distinct Upper Cretaceous 
forms, one having a scatter of long, stout, simple spines, the other a dense matte 
of very short, fine spines ; neither resembles Ehrenberg's figures at all closely. 
The second of Reade's forms was also figured, again as X. hirsutum, by White (1842) 
and has subsequently been designated a distinct species, Baltisphaeridium whitei 
(Deflandre & Courteville 1939) Downie & Sarjeant 1963. 

Pritchard (1841 : 187, pi. 12, fig. 512) figured as X. hirsutum a fourth morphologi- 
cally distinct form from the Upper Cretaceous globular, and with a very sparse cover 
of short, stout spines. This clearly represents a distinct species, but it has not been 
redescribed and the holotype is lost. 

In 1932, O. Wetzel illustrated a form from the Baltic Upper Cretaceous, which he 
named Hystrichosphaera hirsuta forma minor (pi. 3, fig. 13) ; this was described and 
refigured by him (1933 : 91, pi. 4, fig. 26). It was of small size (shell diameter 
24-28^) with numerous (50-60) simple, stout spines of moderate length, quite 
comparable to Ehrenberg's figure. Forms from the Dutch Upper Cretaceous were 
described and figured as forma minor by de Wit (1943 : 381-83) ; his text-figure 
ga corresponds broadly to Wetzel's description, but his text-figure gb shows a form 
with very numerous, extremely abbreviate spines, quite unlike Wetzel's description 
and constituting yet a sixth morphological type! 

Wetzel also described and figured a second form, which he named H. cf. hirsuta 
forma varians (1932, pi. 3, fig. n ; 1933 : 93, pi. 4, figs. 27-29). This has quite 
long spines, sometimes branching at their tips, and a shell surface bearing a pattern of 
low ridges. One of his figures (pi. 4, fig. 29) indicates possession of an archaeopyle. 
Forms from the Dutch Upper Cretaceous were figured under this name by de Wit 
(1943, text-fig. zoa, b). 

In 1937, Deflandre transferred the species hirsutum to his genus Hystrichosphaeridi- 
um, commenting : " It is quite certain that neither of the forms described by 0. 
Wetzel . . . corresponds to the species of Ehrenberg.". He suggested, but did not 
firmly propose, elevation of forma minor to specific status, as Hystrichosphaeridium 
minor. In the same paper, a new Upper Cretaceous species was described, having a 
surface divided into more or less triangular, concave fields and bearing appendages 
of very variable character (relatively slender, simple or branching spines, together 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 159 

with broader processes, branching strongly and with tips secondarily branched), 
the bases of adjacent appendages being connected by striae on the shell surface. 
This was named Hystrichosphaeridium striolatum (Deflandre 1957 : 72, pi. 15, figs. 
1,2); it was again figured by Deflandre & Courteville (1939, pi. 3, fig. 2). 

In 1941, Maria Lejeune-Carpentier re-examined Ehrenberg's material and relocated 
the holotype ; it is contained in Slide XXVI of his series " Feuerstein von Delitzsch " 
and is in the Institut fur Palaontologie und Museum der Humboldt-Universitat, 
Berlin ; it is labelled in pencil " X. hirtum " , obviously in error. Lejeune-Carpentier 
comments wryly : " C. G. Ehrenberg published . . . only a very rough drawing, as 
likely to mislead his successors as to guide them." Her re-examination showed the 
shell surface to be divided into striated fields ; the appendages were normally simple 
and several were found to be " united in pairs by a sort of web." She concluded : 
" What seems certain is the identity of H. striolatum Defl. with Ehrenberg's species " 
and she retained the name hirsutum for this conjoint species. 

De Wit (1944) figured a form from the Dutch Upper Cretaceous as H. hirsutum 
(unnumbered text-figure). This had simple, stiff spines : it closely resembled one of 
the forms he had previously figured (1943, text-fig. 10a) as H. hirsutum forma 
varians and also resembled Ehrenberg's figures, but the species represented does not 
accord with Lejeune-Carpentier's redescription of the holotype. 

In 1946, Deflandre discussed the taxonomic position and commented : " The 
figure of Ehrenberg . . . has as legend " X. hirsutum (?) from a flint from Delitzsch," 
X. hirsutum (without ?) being given as ' living at Berlin ' . . . It is thus not possible 
now to utilize the name X. hirsutum Ehr. and to make of it a Hystrichosphaeridium 
hirsutum (Ehr.), as Maria Lejeune-Carpentier wishes and . . . with very diverse 
meanings. The microfossil rediscovered at Berlin, whether or not it served as a 
model for Ehrenberg, being, according to Mme. Lejeune-Carpentier, identical to 
H. striolatum Defl., must thus be catalogued under this latter name." 

Deflandre's comments and proposals are wholly correct. However, in 1948, 
Andre Pastiels described Eocene forms from Belgium under the names Hystricho- 
sphaeridium cf. hirsutum Ehrbg. and H. cf. hirsutum forma minor. Subsequently 
Cookson (1953) described an Australian Tertiary form as H. cf. hirsutum : and 
Cookson & Eisenack (1958) applied this name to globular forms with short, simple 
spines from the Lower Cretaceous of Australia and Papua. In i960, Klement, 
mentioning this form in discussion, transferred it to the genus Baltisphaeridium. 
A further complication was introduced by W. Wetzel (1952 : 401). On the basis that 
Ehrenberg's type specimen, when re-located by Lejeune-Carpentier, bore the 
manuscript name H. hirtum (interpreted by her as an accidental mis-spelling), he 
employed the name Hystrichosphaeridium hirtum for forms from the Baltic Danian. 
He figured three forms as " H. cf. hirtum " (1952, text-figs. 17-19). One of these is 
spherical, with moderately long, simple spines (text-fig. 17) ; the second (text-fig. 18) 
is oval in outline, with simple spines of moderate length ; and the third (text-fig. 19) 
is also ovoidal, with long, simple or branching spines. The two latter forms are in 
fact more comparable to Prolixosphaeridium xanthiopyxides (Deflandre). Wetzel 



i6o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

further complicated matters by designating other forms " H. cf. striolatum " (pp. 
399-400, text-figs. 13, 14) : both forms show " archaeopyles ", but neither appears 
truly comparable to Ueflandre's species. 

In a second paper describing Danian assemblages, Wetzel (1955 : 38, text-fig. 11) 
reiterated his proposals and described a new form, under the name H. hirtum subsp. 
amplum. The text-figure shows a spherical form with short, stiff spines, again more 
approaching Ehrenberg's text-figure than the specimen as redescribed. 

The name striolatum has been employed in equal measure — by Valensi (1955 : 593, 
pis. 4, fig. 10 ; pi. 5, fig. 3) in describing French Cretaceous forms from Magdalenian 
worked flints ; by Gocht (1959 : 73, pi. 7, fig. 10) who described forms from the 
German Lower Cretaceous as H. cf. striolatum ; and by Gorka (1963 : 68-70, pi. 10, 
fig. 6-7, text-pl. 8, figs. 5-6) who used the same name to designate forms from the 
Upper Cretaceous of Poland. 

Downie & Sarjeant (1963, pp. 91-2) compromized by including both names 
(hirsutum and striolatum) in their list of species attributable to Baltisphaeridium. 
Similarly, both names figure in their list of valid taxa (Downie & Sarjeant 1964: 91, 
97). In the latter work, hirtum is listed as an invalid alteration of hirsutum (p. 166). 

The present situation thus remains confused. One of the authors (R.J.D.) was 
permitted, through the courtesy of Prof. Deflandre, to make a full re-examination of 
the holotype of striolatum which confirmed that Ehrenberg's and Deflandre's species 
are conspecific. For the reasons enunciated by Deflandre (1946), the species must be 
designated striolatum. The name hirtum, whether or not originally written in error, 
was merely pencilled on to a slide by Ehrenberg and was not validly published until 
1952. It is therefore either an invalid alteration of the name hirsutum or a junior 
synonym of striolatum ; however regarded, it cannot be retained. 

The holotype of the species striolatum (in the laboratoire de Micropleontologie, 
Ecole Pratique des Hautes Etudes, Paris, preparation AH 89, flint S.52) is contained 
in a flint flake. It is here provisionally included in the new genus Exochosphaeridhtm, 
on the basis of similarity in general structure to the type species, E. phragmites. 
However, the apical process characteristic of the genus was not certainly observed, 
nor was an archaeopyle noted. 

In view of the highly doubtful character of the morphology of the three subspecies 
amplum W. Wetzel, minor O. Wetzel and varians O. Wetzel, it is considered that 
their erection to specific status would be inappropriate until a full restudy of the 
holotypes has been undertaken. They are therefore provisionally regarded as 
subspecies of E. striolatum. 



Genus SURCULOSPHAERIDIUM nov. 

Derivation of name. Latin, surculus, branch or twig ; sphaera, a ball — with 
reference to the branched nature of the processes radiating from the central body. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



161 



Diagnosis. Subspherical chorate cysts bearing a moderate number of intra- 
tabular processes, considered to reflect the tabulation 4', 6", 6c, 6'", ip, 3"". Proces- 
ses solid, closed distally and branched. Archaeopyle apical. 

Type species. Hystrichosphaeridium cribrotubiferum Sarjeant i960. Upper 
Jurassic (Cardioceras cordatum Zone) ; England. 

Remarks. The processes usually show a distinct circular arrangement on the 
surface of central body. The cingular processes are distinctive, being deeply furcate, 
and with the archaeopyle make orientation easy. 

Surculosphaeridium cribrotubiferum (Sarjeant) 
PL 9, fig. 6 ; Text-fig. 41 

i960. Hystrichosphaeridium cribrotubiferum Sarjeant : 137, pi. 6, figs. 2, 3, text-fig. 1. 

Emended diagnosis. Subspherical central body bearing moderate number of 
solid, distally closed, perforate processes. Processes variably branched, sometimes 
deeply, especially cingular processes. Processes reflect a tabulation of 4', 6", 6c, 6'", 
IP. 3""- 

Holotype. B.M.(N.H.) slide "^.51735(1). Upper Jurassic (Oxford Clay, Cardio- 
ceras cordatum Zone) ; England. 

Dimensions. Holotype : overall diameter y$\x, diameter of central body 43 by 
39[x, length of processes up to 24(x. Range : overall diameters 6o-8opL. Number of 
specimens measured, 8. 





Fig. 41. Surculosphaeridium cribrotubiferum (Sarjeant) . Holotype. Tabulation as reflec- 
ted by the processes. Left, oblique ventral view ; right, oblique dorsal view, x 
c. 600. 



i6j 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Remarks. The diagnosis of this species has been emended to draw attention to 
the closed processes, which reflect a definite tabulation characteristic of the genus and 
the presence of an archaeopyle. The processes were originally considered to be open 
distally ; however, full re-examination of the holotype at high magnifications has not 
confirmed this. 



Surculosphaeridium vestitum (Deflandre) 
PI. 9, fig. 8 ; Text-fig. 42 



1938 
1938 
1947 
1952 
1955 
1 960c 



Hystrichosphaeridium vestitum Deflandre 
Hystrichosphaeridium vestitum Deflandre 
Hystrichosphaeridium vestitum Deflandre 
Hystrichosphaeridium vestitum Deflandre 
Hystrichosphaeridium vestitum Deflandre 



189, pi. 11, figs. 4-6. 
Deflandre : 688, text-fig. 3. 
Deflandre, text-fig. 1, no. 3. 
Deflandre, text-fig. 7. 
Valensi : 587, pi. 2, fig. 8. 



Baltisphaeridium vestitum (Deflandre) Sarjeant : 397, pi. 13, fig. 8, pi. 14, figs. 13, 14. 



1962a. Baltisphaeridium vestitum (Deflandre) : Sarjeant, pi. 12, figs. 3, 5, 6. 

Remarks. The holotype, from the Oxfordian of France, has been restudied by 
two of the authors (R.J.D. and W.A.S.S.), through the courtesy of Prof. Deflandre ; 
and the specimens figured by Sarjeant (1962a) from the Oxfordian of England have 
also been re-examined in the light of recent studies. The processes of this species are 
extremely variable in form, so making the elucidation of the reflected tabulation very 
difficult. The processes are intratabular, the larger ones reflecting one plate of the 
original dinoflagellate theca, while some of the finer ones, in contrast, occur in twos 
and threes and represent a larger process which has been subdivided down to the 
surface of the central body. Thus two or three of these processes may reflect a single 
plate. The most distinctive and characteristic processes are the ones lying in the 
cingular zone. These are either deeply furcate or completely divided into two finer 





Fig. 42. Surculosphaeridium vestitum (Deflandre). Position of cingular processes. Left, 
dorsal view ; right, ventral surface by transparency. V. 51736(1). x c. 650. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



163 



processes. Such cingular processes are especially characteristic of the genus 
Surculosphaeridium , and make specimen orientation comparatively easy. The form 
of the processes and the exact distribution of the non-cingular processes, although 
difficult to determine, indicate that this species does belong to this genus. 

Material (figured). B.M.(N.H.) slide ¥.51736(1). Lower Oxfordian, Dorset, 
England. Upper Jurassic, England. 

Dimensions. Figured specimen : diameter of central body 37 by 47(jl, length of 
processes up to 30fi. 

Surculosphaeridium longifurcatum (Firtion) 
PI. 8, figs. 7, n, Text-figs. 43, 44 

1952. Hystrichosphaeridium longifurcatum Firtion : 157, pi. 9, fig. 1 ; text-fig. 1, H, K, L 

and M. 
1963. Baltisphaeridium longifurcatum (Firtion) Downie & Sarjeant : 91, 

Description. A number of specimens have been found in the British Cenomanian 
which appear to be comparable to Firtion's species from the Cenomanian of France. 

The central body is subspherical. The periphragm is smooth and gives rise to a 
more or less constant 26 processes in a complete specimen. An angular archaeopyle 
is commonly present, the detached apical region bearing 4 apical processes. The 
processes are closed distally and are rather variable in form, being simple, lobate 
foliate or digitate. Some of the processes, particularly those marking the cingulum, 
are deeply branched. In the Upper Cenomanian particularly, the cingular processes, 
each reflecting a cingular plate, may be completely subdivided. Thus there appears 
to be two instead of one cingular process for each plate. 




Fig. 43. Surculosphaeridium longifurcatum (Firtion). Tabulation as reflected by the pro- 
cesses. Left, top lateral view ; right, bottom lateral view. PF. 3042(1). x c. 800. 



164 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



The presence of an apical archaeopyle and the distinctive deeply furcate cingular 
processes make orientation of this species relatively easy. A number of well preserved 
specimens were studied and from the positions of the intratabular processes the 
reflected tabulation appeared to be 4', 6", 6c, 6'", ip, 3'". The test of the original 
dinoflagellate is tentatively reconstructed in the accompanying figure (Text-fig. 41). 

The reflected tabulation of S. longifnrcatum is the same as in 5. cribrotubiferum 
(Sarjeant, i960) ; however, the latter possesses characteristically perforate processes. 

Material (Figured). PI. 8, fig. 11, Geol. Surv. Colin. PF.3042(i). Lower Chalk, 
H.M. Geological Survey Borehole, Fetcham Mill, Surrey at 840 feet depth. Upper 
Cretaceous (Cenomanian). Another specimen, PI. 8, fig. 7, FM. 730/2, at 730 feet 
depth. 

Dimensions. Figured specimens : diameter of central body 32 by 37^, length 
processes 20-24^. Range, lateral view : diameter of central body 30-47^ ; apical 
view : diameter of central body 36-50^ ; length of processes i4-2()[x. Mean 
diameter of archaeopyle, 20[jl. Number of specimens measured, 24. 




/' / 3 " 


4" \ «* 


_£i-L__?i__ 


4c 1 


\ 2"'\ 3'" 


4'" / 5* 





Fig. 44. Surculosphaeridium longifurcatum (Firtion). 
tabulation of the dinoflagellate. 



The probable original 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 165 

Genus EXOCHOSPHAERIDIUM nov. 

Derivation of name. Greek, exochos, projecting or prominent ; sphaera, 
ball — with reference to the distinctive nature of the apical process. 

Diagnosis. Subspherical chorate cysts bearing numerous, commonly simple, 
closed processes. Apical process larger than normal processes and irregularly 
branched. Archaeopyle precingular. 

Type species. Exochosphaeridium phragmites sp. nov. Upper Cretaceous (Ceno- 
manian) ; England. 

Remarks. The processes are commonly acuminate, often joining proximally, but 
may be branched. Only rarely can any alignment of these processes be observed. 
The apical process makes orientation easy and indicates that the archaeopyle is 
precingular. Detached archaeopyle plates have been found and these show the 
characteristic precingular shape. 

Exochosphaeridium phragmites sp. nov. 

PI. 2, figs. 8 — 10 

Derivation of name. Latin, phragmites, a reed — with reference to the reed-like 
shape of the processes of this species. 

Diagnosis. Central body subspherical to oval, possessing a pitted surface and 
bearing numerous acuminate processes. Processes solid or fibrous, broad-based, 
bases of adjacent processes often confluent. Distinctively branched apical process 
present and commonly a precingular archaeopyle. 

Holotype. Geol. Surv. Colin. PF.3035(3). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey at 840 ft. depth. Upper Cretaceous (Ceno- 
manian). 

Paratype. Geol. Surv. Colin. PF.3043(i). H.M. Geological Survey Borehole, 
Fetcham Mill, Surrey at 810 feet depth. Upper Cretaceous (Cenomanian). 

Dimensions. Holotype : diameter of central body 49 by $6\l, length of processes 
up to 22(x. Paratype : diameter of central body 33 by 36^, length of processes up to 

22(X. 

Description. The fibrous processes may occasionally be slightly perforate. 
Division of a process into two often takes place medially, and more rarely distally. 
The processes may terminate distally in a point or may be blunted. The arrangement 
of the processes usually appears to be haphazard and in only one specimen, the para- 
type, can any alignment be observed. In this specimen a definite alignment can be 
seen on both sides of the cingulum running parallel to this structure. An apical 
process and an archaeopyle are present, thus making orientation easy. The apical 
process is very distinctive, being foliate in shape ; it is situated near the edge of the 
archaeopyle. The position of this process indicates that it must be an apical process 
and that the archaeopyle is precingular. E. phragmites occurs throughout the 
Cenomanian of England. 



166 MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 

Remarks. Superficially E. phragmites resembles Baltisphaeridium striolatum 
Deflandre, the holotype of which was examined by one of the authors (R.J.D.) by 
kind permission of Professor Deflandre. B. striolatum, however, has a definitely 
striated periphragm on the surface of the central body and neither a distinctive apical 
process nor an archaeopyle has been observed. It must be made clear, however, 
that the holotype of B. striolatum is extremely dark and the lower surface, which may 
possess an archaeopyle and an apical process, is not observable. 

OTHER SPECIES 

The following species are here included in Exochosphaeridium gen. nov. on the basis 
of similarity in structure and process pattern : 

Exochosphaeridium palmatum (Deflandre & Courteville 1939). Upper Cretaceous ; 
France. 

Exochosphaeridium striolatum (Deflandre 1937a). Upper Cretaceous ; France. 

The following species is tentatively referred to this genus, subject to subsequent 
confirmation of the precingular position of the archeopyle : 

? Exoxhosphaeridium pseudhystrichodinium (Deflandre 19370). Upper Cretaceous ; 
France. 



Genus CLEISTOSPHAERIDIUM nov. 

Derivation of name. Greek, kleistos, shut, closed ; sphaera, ball — in reference 
to shell shape and the closed nature of the processes. 

Diagnosis. Chorate dinoflagellate cysts having spherical to ovoidal central 
bodies bearing numerous processes, typically closed distally and without communica- 
tion to endocoel. Number of processes typically exceeding 50 ; processes showing 
no definite alignment, so that the tabulation is not determinable. Archaeopyle 
apical, with zigzag margin. 

Type species. Cleistophaeridium diver sispinosum sp. nov. Eocene ; England. 

Remarks. It is not clear whether the processes of this genus are intertabular or 
intratabular ; nor is there any differentiation between processes which would enable 
the establishment of orientation. The shape and size of the archaeopyle, however, 
strongly suggests that it is apical. 

All Mesozoic and Tertiary species, formerly attributed to Baltisphaeridium, which 
show an apparent apical archaeopyle and which cannot be related to Surculosphaeri- 
dium or Prolixosphaeridium, are provisionally reattributed to this genus. Species 
are included whose process numbers are relatively low ; it is probable that re- 
examination of these will necessitate their removal to other genera as soon as the 
reflected tabulation is determined. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 167 

Cleistosphaeridium diversispinosum sp. nov. 
PL 10, fig. 7 

Derivation of name. Latin, diversus, different ; spinosus, thorny — with 
reference to the variable shape of the processes. 

Diagnosis. A Cleistospharidium with granular wall and polygonal archaeopyle. 
Processes solid, taeniate or tubular, usually slender and proximally expanded. 
Distal end forked or expanded. 

Holotype. B.M.(N.H.) slide ¥.51750(1). Eocene (London Clay) ; Whitecliff. 

Dimensions. Holotype : diameter of body 38^, length of processes, g-i6\i. 
Observed range : diameter of body 38-43^, length of processes 7~23[x. Number of 
specimens measured, 5. 

Description. This species is distinguished by the variable nature of the process 
ends. The expanded termination may be bifurcate, orthogonal or patulate, one 
branch may be larger than the other. The edges are usually denticulate and the 
processes may be up to 5;x wide ; but are usually about 2jx. There is more than one 
process to a plate. 

Occurrence. London Clay ; Whitecliff, Enborne and Sheppey. 

Remarks. Only Cleistosphaeridium pectiniforme (Gerlach) 1961 comb. nov. 
resembles C. diversispinosum to any degree. It has widely forked processes with 
spinose margins ; it does not, however, have the variability of process ending shown 
by our species. The species pectiniforme is reattributed to the genus Cleistosphaeri- 
dium provisionally on the basis of its similarity to C. diversispinosum, despite lack 
of knowledge of its mode of archaeopyle formation. 



Cleistosphaeridium ancoriferum (Cookson & Eisenack) 

PI. 9- %• 1 

1960a. Hystrichosphaeridium ancoriferum Cookson & Eisenack : 8, pi. 2, fig. 11. 
1964. Hystrichosphaeridium ancoriferum Cookson & Eisenack ; Cookson & Hughes : 47, pi. 9, 
fig- 7- 

Description. The specimens of C. ancoriferum found in the Lower Cenomanian 
of England, first described and figured by Cookson & Hughes (1964) strongly resemble 
those examples recorded from Australia (Cookson & Eisenack, 1960a). Many of the 
specimens from the Fetcham Mill Borehole possess a 6-sided apical archaeopyle 
the shape of which is often difficult to determine due to distortion. However, 
detached apical regions are relatively abundant. The processes are hollow, the 
cavity often being constricted to some extent, and closed distally and proximally. 
They do not appear to be aligned to any noticeable extent. 

C. ancoriferum has been recorded from the Albian and Cenomanian of England and 
Australia. 



168 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Material (figured). Geol. Surv. Colin, slide PF.3044(i). Lower Chalk, H.M. 
Geological Survey Borehole, Fetcham Mill, Surrey, at 810 feet depth. Upper 
Cretaceous (Cenomanian). 

Dimensions. Figured specimen : diameter of central body 32 by 4ijx, length of 
processes up to 9jx. Range : diameter of central body 20-45 ja, length of processes 
up to 9(x. Number of specimens measured, 30. 

Remarks. As with Cookson & Hughes (1964), difficulty was met with when 
trying to distinguish C. ancoriferum from Chlamydophorella nyei (Cookson & Eisenack 
1958), since the outer membrane and apical prominence of the latter are often obscure. 
The processes of C. nyei, however, are finer and shorter than those of C. ancoriferum. 

Cookson & Eisenack (1960a) comment on the " transparent tips " of the processes 
of C. ancoriferum. The cavities are in fact closed by a thin, tranparent membrane. 
This character may well indicate a close relation to Chlamydophorella. The species 
Cleistosphaeridium ancoriferum may have arisen by the progressive restriction of a 
formerly continuous membrane ; or alternatively, Chlamydopherella may have 
arisen by the extension of a membrane which originally merely tipped the processes. 

Cleistosphaeridium heteracanthum (Deflandre & Cookson) 

PL 2, figs. 6, 7 

1955. Hyslrichosphaeridium heteracanthum Deflandre & Cookson : 276, pi. 2, figs. 5, 6 ; text- 
figs. 40, 41. 

1961a. Hystrichosphaeridium heteracanthum Deflandre & Cookson ; Cookson & Eisenack : 73, 
pi. 12, fig. 14. 

1963. Baltisphaeridium heteracanthum (Deflandre & Cookson) Downie & Sarjeant : 91. 

Remarks. The Cenomanian specimens from England are very similar to the 
forms illustrated by Deflandre & Cookson (1955) from the Upper Cretaceous of 
Victoria, Australia. 

The surface of the central body may be smooth or reticulate. The processes are 
extremely variable in shape but do not vary markedly in length. One complete 
specimen has been found and this possessed one large distinctive process. In all the 
other studied examples this process was absent and there was, in every case, a large, 
well defined, archaeopyle. It is probable, therefore, that the process is apical and that 
the archaeopyle, when developed, is also apical in position. Alignment of the proces- 
ses on the surface of the central body has not been observed. Some difficulty was 
experienced in distinguishing C. heteracanthum from C. multifurcatum (Deflandre). 
The processes of the latter, however, appear to be considerably less varied, most of 
them terminating with a simple bifurcation or being blunted. 

C. heteracanthum is found throughout the Cenomanian of England, and in Australia 
it has been recorded from the Upper Cretaceous and Lower Eocene. 

One specimen of C. heteracanthum illustrated by Deflandre & Cookson (1955, 
pi. 12, fig. 14) appears to possess an apical archaeopyle. For the latter reason this 
species is tentatively placed in the genus Cleistosphaeridium. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 169 

Material (figured). PI. 2, fig. 6, Geol. Surv. Colin, slide PF.304i(2). Lower 
Chalk, H.M. Geological Survey Borehole, Fetcham Mill, Surrey, at 650 feet depth. 
Upper Cretaceous (Cenomanian). Another specimen, PI. 2, fig. 7, at 840 feet depth. 

Dimensions. Figured specimens : diameter of central body 52 by 59fx, length of 
processes up to ij\l. Range of Cenomanian specimens : diameter of central body 
5o-68(x, length of processes up to 17^. Number of specimens measured, 5. 

? Cleistosphaeridium flexuosum sp. nov. 
PL 2, fig. 5 

Derivation of name. Latin, flexuosus, flexuous — with reference to the form of the 
processes. 

Diagnosis. Central body subspherical to elongate, bearing numerous, broadly 
acuminate, processes. All processes of approximately same length, slightly fibrous 
and always flexuous. 

Holotype. Geol. Surv. Colin, slide PF.3045(i). Lower Chalk, H.M. Geological 
Survey Borehole, Fetcham Mill, Surrey at 840 feet depth. Upper Cretaceous 
(Cenomanian.) 

Dimensions. Holotype : diameter of central body 29 by 37(x, length of processes 
up to I7(x. Range : diameter of central body 20 to 45(jl, length of processes up to 
20(x. Number of specimens measured, 4. 

Description. The most distinctive feature of ?C. flexuosum is the flexuous nature 
of the broad fibrous processes. The nature of the surface of the central body is 
difficult to determine and the presence of an archaeopyle has not been recorded. 

This is a rare species throughout the Cenomanian of England. 

Remarks. The nature of the processes easily differentiate ?C. flexuous from all 
previously described species. This species is tentatively placed in Cleistosphaeridium 
on the general form of the central body and processes. 

Cleistosphaeridium disjunctum sp. nov. 
PL 11, fig. 9 

Derivation of name. Latin, dis, asunder ; junctus, joined. 

Diagnosis. A Cleistosphaeridium with granular central body and polygonal 
archaeopyle. Numerous processes hollow, unbranched, closed distally and proxim- 
ally, with distal terminations blunt, acuminate, or bearing small spines. Processes 
regularly arranged. 

Holotype. B.M.(N.H.) slide ¥.51739(2). Eocene (London Clay) ; Whitecliff. 

Dimensions. Holotype : diameter of central body 47-54^, length of processes 
io-i5fi.. Observed range : diameter of body 30-56jx, process length 10-19^. Num- 
ber of specimens measured, 13. 



170 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. Attempts to make subdivisions on the type and pattern of processes 
have been fruitless ; the species is a very variable one. The wall also shows consider- 
able variation in thickness. 

The processes are from a quarter to a half of the body diameter and are hollow. 
The process length in an individual is constant, as are the process terminations. The 
number of processes exceeds 50. Plates can be recognized on damaged specimens 
and the number of processes ranges from four to seven on each plate. 

Occurrence. London Clay ; Whitechff and Enborne. 

Remarks. C. disjunctum resembles Baltisphaeridium densicomatum (Maier) which 
however splits equatorially and sometimes has forked processes. B. iaculigerum 
Klement has longer processes and the archaeopyle is unknown. 

In view of the regular arrangement of the processes, a feature not typical of the 
genus, the allocation of this species to Cleistosphaeridium must be regarded as provi- 
sional. 

OTHER SPECIES 

The following species, formerly attributed to Baltisphaeridium, are here provision- 
ally reattributed to Cleistosphaeridium gen. nov., on the basis of their apparent 
possession of an apical archaeopyle and in absence of knowledge of their reflected 
tabulation (if any). Species of especially doubtful character are differentiated with 
a question mark : 

Cleistosphaeridium ashdodense (Rossignol 1962). Miocene ; Australia. 

} Cleistosphaeridium danicum (W. Wetzel 1952). Paleocene (Danian) ; Baltic. 

Cleistosphaeridium echinoides (Maier 1959). Oligocene ; Germany. 

Cleistosphaeridium ehrenbergi (Deflandre 19476). Upper Jurassic ; France. 

Cleistosphaeridium israelianum (Rossignol 1962). Quaternary ; Israel. 

Cleistosphaeridium leve (Maier 1959). Oligocene-Miocene ; Germany. 

Cleistosphaeridium lumectum (Sarjeant 1960a). Upper Jurassic ; England. 

Cleistosphaeridium machaerophorum (Deflandre & Cookson 1955). Miocene ; 
Australia. 

Cleistosphaeridium multifurcatum (Deflandre 1937a). Upper Cretaceous ; France. 

? Cleistosphaeridium oligacanthum (W. Wetzel 1952). Paleocene (Danian) ; 
Baltic. 

Cleistosphaeridium pectiniforme (Gerlach 1961). Oligocene ; Germany. 

Cleistosphaeridium pilosum (Ehrenberg 1954). Upper Jurassic ; Poland. 

Cleistosphaeridium polytrichum (Valensi 1947). Middle Jurassic ; France. 
? Cleistosphaeridium spiralisetum (de Wit 1943). Upper Cretaceous ; Netherlands. 

Cleistosphaeridium tiara (Klumpp 1953). Eocene ; Germany. 

Cleistosphaeridium tribuliferum (Sarjeant 19626). Upper Jurassic ; England. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Genus PROLIXOSPHAERIDIUM nov. 



171 



-with 



Derivation of name. Latin, prolixus, stretched out long ; sphaera ball- 
reference to the shape of the central body. 

Diagnosis. Shell shape elongate ovoidal to ellipsoidal, one pole (apical) typically 
lost in archaeopyle formation. Opposite pole occupied by one or two antapical 
processes. Remaining processes arranged in distinct rows encircling test ; these 
rows slightly offset at a position corresponding to sulcus. Number of processes 
exceeding 30. Processes closed proximally, closed or open distally : their distal 
terminations simple ; flaring in varied fashion ; or briefly furcate. Shell surface 
bearing cover of coarse granules or very short, simple spinelets, or lacking such 
ornamentation. 

Type species. Prolixosphaeridium deirense, sp. nov. Lower Cretaceous (Middle 
Barremian) ; England. 

Remarks. A group of Mesozoic dinoflagellate cysts exhibit an elongate central 
body with a terminal archaeopyle. Their distinctive character and unity of form 
merits taxomonic recognition at generic level. The arrangement of the processes 
suggests that they are intratabular, corresponding perhaps to crest nodes, but 
prolonged study of many individuals would be necessary before this could be 
confirmed. 



Prolixosphaeridium deirense sp. 

PI. 3, fig. 2 ; Text-fig. 45 



nov. 



Derivation of name. Latin, deirense, of Deira, the ancient kingdom occupying 
what is now East Yorkshire. 





Fig. 45. Prolixosphaeridium deirense gen. et sp. nov. Left, ventral view ; 
right, dorsal view. X c. 1000. 



i 7 2 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Diagnosis. A Prolixosphaeridium having an elongate ovoidal central body 
bearing 60-65 processes. Processes simple or briefly bifurcate (bifurcations unequal- 
ly long), closed proximally, dominantly or constantly closed distally. Two processes 
occupying antapical pole ; remaining processes showing alignment in rows, encircling 
test and offset at a position corresponding to sulcus. Apex typically lost in archaeo- 
pyle formation ; about six rows of processes present between archaeopyle and 
antapex, gap between third and fourth row probably corresponding to cingulum. 
Test surface granular and bearing dense cover of very short spinelets. 

Holotype. B.M.(N.H.) slide ¥".51727(2), Speeton Clay, Shell West Heslerton 
boring, Yorkshire, Lower Cretaceous (Middle Barremian). 

Dimensions. Holotype : overall length (apex lacking) 62jj. ; overall breadth 
46fi. ; shell length (apex lacking) ^o\i ; breadth 28[x ; spines c.io-i2[i. long, spinelets 
i-i-5[x long. Dimensions of other specimens closely similar. 

Description. The distribution of the processes on the epitheca is into three 
rows ; these appear to respectively comprise 9, 10 and 10 processes. Distribution of 
processes on the hypotheca was less easily determined. Two rows of processes were 
present posterior to the presumed cingulum, each apparently comprising 9 processes ; 
and some 9 further processes clustered round the antapex, probably but not certainly 
representing a sixth process row. 

The short spinelets form a stubble on the granular surface of the periphragm. 

Remarks. This species was encountered only in the 39 foot horizon in the West 
Heslerton Borehole. It closely resembles the Upper Jurassic species P. mixtispino- 
sum (Klement 1960), differing in the broader shell shape (length-width ratio of 
P. mixtispinosutn consistently greater than 2:1, against a length-width ratio in 
P. deirense consistently markedly less than 2 : 1) ; in the furcate character of some 
processes ; and in the somewhat shorter spinelets. These distinctions are minor ; 
there can be no doubt that P. deirense and P. mixtispinosum are closely related. 



Prolixosphaeridium granulosum (Deflandre) 

1937. Hystrichosphaeridium xanthiopyxides var. granulosum Deflandre : 29, pi. 16, fig. 4. 

1955. Hystrichosphaeridium xanthiopyxides var. granulosum Deflandre ; Valensi : 594, pis. 3, 
fig. 7, pi. 5, fig. 16. 

1957. Hystrichosphaeridium xanthiopyxides var. granulosum Deflandre ; Downie : 426, text- 
fig. 46. 

i960. Baltisphaeridium xanthiopyxides var. granulosum (Deflandre) Klement : 59, 

1962a Baltisphaeridium granulosum (Deflandre) ; Sarjeant : 264, pi. 2, fig. 14, text-fig. 8c. 

Remarks. This species, which has a known range from Upper Jurassic to 
Upper Cretaceous, is represented in the London Clay at Whitecliff and Enborne ; 
it is, however, possible that these specimens are derived. 

It differs from P. deirense in having only approximately 30 processes, organized 
into rows, with one antapical process. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 173 

OTHER SPECIES 

The following species are here included in the genus Prolixosphaeridium nov., on 
the basis of shape, character of processes and possession of an apical archaeopyle : 

Prolixosphaeridium mixtispinosum (Klement i960). Upper Jurassic ; Germany. 

Prolixosphaeridium parvispinum (Deflandre 1937a). Upper Cretaceous ; France. 

The following species, inadequately described and figured, is doubtfully referred 
to this genus : 

IProlixosphaeridium xanthiopyxides (O. Wetzel 1933). Upper Cretaceous ; 
Germany. 

OTHER MESOZOIC AND CAINOZOIC SPECIES ATTRIBUTED TO BALTISPHAERIDIUM 

In the preceding section, the bulk of post-Palaeozoic species, hitherto placed in 
Baltisphaeridium, have been reattributed to four new genera on the bases of shape, 
process arrangement and possession of archaeopyles. The species Baltisphaeridium 
spinosum (White) is considered in the previous chapter ; it is shown to be probably 
synonymous with Hystrichodinium pulchrum Deflandre but since the holotype of B. 
spinosum is lost, restudy is not possible. The abandonment of the name spinosum is 
therefore proposed. The species Baltisphaeridium geometricum (Pastiels) was 
originally placed in the genus Hystrichosphaeridium and was then a junior homonym 
of a species proposed by Deflandre (1945) ; since invalid at the time of publication, 
this name must be rejected. Pastiel's forms are attributable to the genus Wetzeliella 
and are discussed more fully on p. 192. 

The holotypes of the two species, Baltisphaeridium ferox (Deflandre) and B. tri- 
dactylites (Valensi) were re-examined recently by one of the authors (R.J.D.) in 
consultation with Prof. Deflandre. On the basis of this re-examination, their 
reattribution to Hystrichokolpoma is here proposed. Reattribution of two species, 
(Baltisphaeridium neptuni Eisenack 1958 and B. triangulatum Gerlach 1961) to the 
genus Achomosphaera is proposed on pp. 51, 52 ; and in the discussion of the genus 
Hystrichosphaeridium and its allies (see pp. 53-105) the reattribution of two further 
species to new genera is proposed, Baltisphaeridium dictyophorum (Cookson & 
Eisenack) becoming Oligosphaeridium and B. striatoconus (Deflandre & Cookson) 
becoming Litosphaeridium. 

Five further species currently attributed to the genus Baltisphaeridium appear also 
to merit reattribution. Four species from the German Tertiary, three of them attri- 
buted by Maier (1959) to her invalid genus Galea and subsequently reattributed by 
Downie & Sarjeant (1963) to Baltisphaeridium (B. galea ; B. lychneum ; B. rehdense ; 
and B. twistringense) are herewith tentatively reattributed to the genus Areoligera on 
the basis of archaeopyle structure. The species Baltisphaeridium placacanthum (De- 
flandre & Cookson) is herewith reattributed to Systematophora, since the processes 
show the grouping characteristic of the latter genus. 

A residue of Mesosoic and Tertiary species remain, which either appear definitely 
acritarchs or whose morphology is not at present sufficiently well known for any 



174 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

reattribution to be made. These are, for the time being, left in the genus Balti- 
sphaeridutm ; they are as follows : 

Baltisphaeridiiim armatum (Deflandre, 1937) Downie & Sarjeant 1963. Upper 
Cretaceous ; France. 

B. asteroideum (Maslov 1956) Downie & Sarjeant 1963. Upper Cretaceous ; 
Cauacusus, U.S.S.R. 

B. clavicidorum (Deflandre 1938) Downie & Sarjeant 1963. Upper Jurassic ; 
France. 

B. clavispinulosum Churchill & Sarjeant 1963. Quaternary ; Australia. 

B. densicomatum (Maier 1959) Gerlach 1961. Oligocene ; Germany. 

B. denticidatum (Courteville in Deflandre 1946) Downie & Sarjeant 1963. Upper 

Cretaceous ; France. 
B.l difformc (Pritchard 1841) Downie & Sarjeant 1963. Upper Cretaceous ; 

England. 

B. downiei Sarjeant 1960a, Upper Jurassic ; England. 

B. echiniplax Churchill & Sarjeant 1963. Quaternary ; Australia. 

B . fimbriatum (White 1842) Sarjeant 1959. Upper Cretaceous ; England. 

B. gilsonii (Kufferath 1950) Downie & Sarjeant 1963. Quaternary ; Belgium. 

B. horridum (Deflandre 1937) Downie & Sarjeant 1963. Upper Cretaceous ; 
France. 

B. hitgnonioti (Valensi 1955) Downie & Sarjeant 1963. Cretaceous ; France. 

B. intermedium (O. Wetzel 1933) Downie & Sarjeant 1963. Upper Cretaceous ; 
Baltic. 

B. longofdum (Maier 1959) Downie & Sarjeant 1963. Oligocene ; Germany. 

B. malleoferum (White 1842) Downie & Sarjeant 1963. Upper Cretaceous ; 
England. 

B. mariannae (Philippot 1949) Downie & Sarjeant 1963. Upper Cretaceous ; 
France. 

B. panniforme Gerlach 1961. Oligocene ; Germany. 

B. pattei (Valensi 1948) Sarjeant 1960a. Middle Jurassic ; France. 

B. paucifurcatum (Cookson & Eisenack 1961ft) Downie & Sarjeant 1964. Eocene ; 
Australia. 

B. pectiniforme Gerlach 1961. Oligocene ; Germany. 

B. plicatum (Maier 1959) Downie & Sarjeant 1963. Oligocene ; Germany. 

B. (?) polyceratum Takahashi 1964. Oligocene ; Japan. 

B. polyozon Brosius 1963. Oligocene ; Germany. 

B. quaternarium Churchill & Sarjeant 1963. Quaternary ; Australia. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 175 

B. saturnium (Maier 1959) Downie & Sarjeant 1963. Miocene ; Germany. 

B. seminudum (W. Wetzel 1952) Downie & Sarjeant 1963. Paleocene (Danian) ; 
Baltic. 

B. spiculatum (White 1844) Downie & Sarjeant 1963. Upper Cretaceous ; 
England. 

B. stimuliferum (Deflandre 1938) Sarjeant 1960c. Upper Jurassic ; France. 

B. sylheti (Baksi 1963) Downie & Sarjeant 1964. Eocene ; Assam, India. 

B. telmaticum Churchill & Sarjeant 1963. Quaternary ; Australia. 

B. tinglewoodense Churchill & Sarjeant 1963. Quaternary, Australia. 

B. varispinosurn Sarjeant 1959. Middle Jurassic ; England. 

B. whitei (Deflandre & Courteville 1939) Downie & Sarjeant 1963. Upper Creta- 
ceous ; France. 

It is apparent, from illustrations and descriptions, that the bulk of these species 
will be demonstrated in the future also to be the cysts of dinoflagellates ; acritarchs 
appear relatively infrequent after the Palaeozoic. Five of the species listed are 
freshwater forms from the Australian Quaternary ; a restudy of their taxonomy is in 
progress. 



176 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

VIII. THE GENUS HYSTRICHOKOLPOM A 

By G. L. WILLIAMS & C. DOWNIE 

INTRODUCTION 

The appearance of Hystrichokolpoma makes it one of the most striking of the 
Tertiary dinoflagellate cysts. It occurs in small numbers throughout the London 
Clay where its excellent preservation enables the tabulation to be determined 
completely in many circumstances. Two previously described and one new species 
are recorded. 

Genus HYSTRICHOKOLPOMA Klumpp 1953 : 388 

Emended diagnosis. Chorate cysts bearing two types of intratabular processes, 
large types with expanded bases, and slender ones. Large processes have proximally 
a quadrate cross section reflecting plate outline. Slender processes delimiting well 
marked cingular and sulcal zone. Cingulum helicoid. Reflected tabulation of 4', 
6", 6g, 5'", ip, 1"". Archeopyle apical tetratabular. 

Type species. Hystrichokolpoma cinctum Klumpp 1953. Eocene ; Germany. 

Discussion. Hystrichokolpoma is a genus with a spherical to ellipsoidal central 
body possessing intratabular processes, radial symmetry and an apical archeopyle. 
Each large process almost completely occupies a single plate proximally assuming 
the outline of the plate leaving only a narrow border all round. Distally these 
processes taper and may be open or closed. They are restricted to the apical, 
precingular, postcingular, antapical and commonly anterior sulcal plates. The 
antapical plate is easily recognizable, having a longer process than the others. The 
slender processes are restricted to the cingular and sulcal zones. The number of 
equatorial processes per plate is constant in an individual but can vary within the 
species as now defined (personal communication from Dr. W. R. Evitt). The apical 
plates are rarely found in position. Breakage along sutures readily occurs when 
attempting to mount specimens of Hystrichokolpoma. Process variation in structure 
and number is considerable and needs careful study. 



Hystrichokolpoma eisenacki sp. nov. 
PI. 17, figs. 1-3 ; Text-fig. 46 

1954. Hystrichokolpoma cinctum Klumpp ; Eisenack : 64, pi. 10, figs. n-14. 

Derivation of name. After Prof. Alfred Eisenack, pioneer worker on fossil 
dinoflagellates. 

Diagnosis. Ellipsoidal central body with wall composed of two closely appressed 
layers — the smooth or granular endophragm and the thinner smooth periphragm. 
Endophragm continuing uninterrupted beneath processes formed from periphragm. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



177 



Processes of two types, large ones with quadrate bases, cylindrical or tapering with 
open ends, and small slender processes, with ends open or closed. Antapical 
process much longer than others. Tabulation typical for genus. Number of slender 
processes on each cingular plate limited to two. Cingulum helicoidal. Anterior 
sulcal process considerably larger than other sulcals. 

Holotype. B.M.(N.H.) slide ¥.51958(1), London Clay ; Sheppey, Kent, 
sample Sh. 3. 




/ 



Fig. 46. Hystrichokolpoma eisenacki sp. nov. Ventral view of holotype showing 
the Tabulation. The archaeopyle is shaded. 



178 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Holotype : diameter of central body 47 by 52(x. Broad processes, 
length up to 30fi, breadth up to 2J\l. Length of slender processes up to 22pL. Range 
of dimensions observed ; diameter of central body 40-57fx. Length of broad 
processes 20-30^. Antapical process up to 47^. Width of broad processes 12-27^. 
Length of slender processes 13-20^. Width of slender processes o-5-4(x. Number 
of specimens measured, 4. 

Description. H. eisenacki is characterized by the broad processes which taper 
distally to a restricted opening with entire or serrate margin. Frequently branching 
off from the large processes are small erect tubules with an open serrate distal 
margin ; commonly there are three or four on each process. The equatorial 
processes are simple or branched, slender with slightly expanded distal openings. 
The four apical plates are rarely present ; the archaeopyle has a broad sulcal notch. 
In the precingular series of plates, plate 6" and its attendant process are considerably 
smaller than the other five plates and processes, being comparable in size to the 
anterior sulcal plate and process. In the postcingular series, plate 1'" and its process 
are the smallest of the series, the other four plates and processes approaching the 
precingulars in size. The longest process, which tapers before expanding distally, 
marks the position of the single antapical plate. This process is usually closed and 
unbranched. There are six sulcal processes, one very large anterior process and five 
very slender open or bifid or acuminate processes lying between plates 1'" and 5'". 
The single posterior intercalary process is little different in size and structure to the 
slender sulcal processes and occupies a position between 1'" and 1"". The apical 
processes are usually simple, occasionally branched, tapering and open distally. 

Occurrence. London Clay, Whitecliff and Enborne and the Oligocene of Sam- 
land, East Prussia (Eisenack 1954). 

Remarks. The authors are indebted to Dr. W. R. Evitt of Stanford University 
for placing at their disposal camera lucida drawings of the holotype of Hystri- 
chokolpoma cinctum Klumpp (1953) and the originals of H. cinctum Klumpp of 
Eisenack (1954) ; they are quite different species. The drawings show that H. 
eisenacki and Eisenack's (1954) specimens of H. cinctum have similar tabulation and 
differ only in that the former has tubular branches, and not pointed spines, arising 
from the broad processes. Both are, however, included within the same species here 
named H. eisenacki. H. eisenacki differs from H. cinctum Klumpp (1953) in the 
dorsal terminations of the broad processes which are more commonly branched, the 
smaller number of cingular processes and the possession of a large anterior sulcal 
process and plate. 

Hystrichokolpoma eisenacki var. turgidum nov. 
PI 17. fig. 5 
Derivation of name. Latin, tuvgidus, inflated, swollen, distended. 

Diagnosis. Central body ovoidal slightly granular, bearing processes of two 
types, broad sub-conical or bulbose, with wide or restricted distal opening and 
slender, simple or bifurcate processes open or closed distally. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 179 

Holotype. B.M.(N.H.) slide ¥.51959(1). London Clay ; Enborne, sample 
E 11. 

Dimensions. Holotype : diameter of central body 40-41^. Length of broad 
processes up to 2ifi. Length of slender processes up to 24[x. Range of dimensions 
observed : diameter of central body 44-56(1. Length of broad processes 20-30^, 
width of broad processes 8-26fx. Length of slender processes i6-28[x, width of 
slender processes usually i-3[x. Number of specimens measured, 3. 

Description. The broad processes of H. eisenacki var. turgidum may be sub- 
conical and widely open distally or bulbose with a restricted opening that has a 
serrate, commonly recurved, margin. Branching similar to that in H. eisenacki can 
occur, but there are rarely more than one or two branches. The longer tapering 
antapical process sometimes has very small tubules arising laterally and appears 
minutely open distally. The broad processes give rise to a characteristic trapezoid 
outline where they join the central body. The slender equatorial processes are 
variable in number, generally being restricted to two per plate, with infrequently 
three occurring. They are open with a digitate or serrate distal margin or they are 
bifurcate. Often they arise in pairs, being united proximally for as much as £ of 
their length. The tabulation is as in H. eisenacki with a reduced sixth precingular 
plate and a large anterior sulcal plate. 

Occurrence. London Clay ; Enborne and Sheppey. 

Remarks. H. eisenacki var. turgidum differs from H. cinctum in the number of 
cingular processes and the presence of a large anterior sulcal plate and process, and 
from the typical form of H . eisenacki in the usual presence of broad processes that 
have three or four branches distally. 



Hystrichokolpoma unispinum sp. nov. 
PI. 17, figs. 6, 7 

Derivation of name. Latin, uni — one ; spina, spine. 

Diagnosis. Central body sub-spherical with thin smooth endophragm, continu- 
ous beneath processes, and thin smooth periphragm. Processes formed from 
periphragm and of two types, broad tapering lagenate, and buccinate more slender 
processes. Reflected tabulation of 4', 6", 6g, 5'", ip, 1"" and at least 5s. Each 
cingular plate possessing only one process. 

Holotype. B.M.(N.H.) slide ¥.51961(1), London Clay ; Whitecliff, sample WC 8. 

Dimensions. Holotype : diameter of central body 39 by 43(0.. Length of broad 
processes up to 29fx, width up to 21 [i. Slender processes, length up to 26[x, width up 
to 5fj.. Range of dimensions observed : diameter of central body 39-5 ifx. Length 
of broad processes 21-29^1, breadth up to 2i[x. Equatorial processes, length i8-26[x, 
breadth up to 5[x. Number of specimens measured, 3. 



180 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Description. The tabulation of H. unispinum is well shown in two specimens 
from the London Clay. There are four apical plates, i' being smaller than the other 
three. The apical processes are tapering, open distally with a serrate or undulose 
margin. Five of the precingular plates and processes are equal in size, the other, 
plate 6", is smaller, more closely approaching the anterior sulcal plate. The equa- 
torial plates each possess one process. The postcingulars are as in H. eisenacki, with 
plate i'" being reduced compared to the other four. The process of the posterior 
intercalary plate is small and the antapical plate is marked by a longer than average 
process. 

The broad processes all appear open distally and may have small tubular branches. 
The equatorial processes are broader than in other species of Hystrichokolpoma and 
are tubiform or buccinate with serrate or undulose distal margins. A few have 
perforations in the wall, irregular in position. The processes may occasionally be 
branched. The posterior sulcal processes are slender and short with digitate 
endings which may be open or closed. 

Occurrence. London Clay ; Whitecliff and Enborne. 

Remarks. The presence of one process only on each cingular plate readily 
distinguishes H. unispinum from other species of Hystrichokolpoma. 

Hystrichokolpoma rigaudae Deflandre & Cookson 
PL 17, fig. 4 



1954 
1955 
1959 
1961 
1962 

1963 
1964 



Hystrichokolpoma rigaudae Deflandre & Cookson, text-fig. 15 (n.n.). 
Hystrichokolpoma rigaudae Deflandre & Cookson : 279, pi. 6, figs. 6-10 ; text-fig. 42. 
Hystrichokolpoma rigaudae Deflandre & Cookson ; Maier : 311, pi. 31, fig. 2. 
Hystrichokolpoma rigaudae Deflandre & Cookson ; Gerlach : 183, pi. 27, figs. 8, 9. 
Hystrichokolpoma rigaudae Deflandre & Cookson ; Rossignol : 134. 
Hystrichocolpoma rigaudae Deflandre & Cookson ; Brosius : 43, pi. 2, fig. 6. 
Hystrichokolpoma rigaudae Deflandre & Cookson ; Rossignol : 89, pi. 2, fig. 5, pi. 3, 
fig. 8. 



Discussion. Specimens of H. rigaudae from the London Clay possess a tabulation 
of 6", 6c, 5'", ip, 1"" and 6a. Plates 6" and 1'" and their attendant processes are 
reduced whilst the anterior sulcal plate is the largest of the six. A few of the broad 
processes and some of the girdle ones are open distally. There seems to be a degree 
of variability in the number of cingular processes, some plates having only one ; 
generally however there are two processes on each cingular plate. 

Dimensions. Observed range in London Clay : diameter of central body 35-481X. 
Length of broad processes up to 3ijx. Length of antapical process up to 39(1.. 
Number of specimens measured, 3. 

Occurrence. London Clay ; Whitecliff, Enborne and Sheppey. H. rigaudae 
has also been recorded from the Eocene and Miocene (or older) of Australia (Deflandre 
& Cookson 1954, 1955), the Middle Oligocene-Middle Miocene (Gerlach 1961), the 
Upper Oligocene (Brosuis 1963) and the Middle Miocene of Germany (Maier 1959) 
and the Pleistocene of Israel (Rossignol 1962, 1964). 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 181 

OTHER SPECIES 

Re-examination of Baltisphaeridium ferox (Deflandre 1937a) Downie & Sarjeant 
1963, B. tridactylites (Valensi 1955), Downie & Sarjeant, 1963 and Hystrichosphaeri- 
dium clavigerum Deflandre 1937a, by Mr. R. J. Davey and Prof. Deflandre, has 
determined that these species should be transferred to the genus Hystrichokolpoma. 

The remaining species attributed to this genus are H. sequanapartus, Deflandre & 
Deflandre-Rigaud 1958, and H. poculum Maier 1959. A single specimen of a form 
very like the former was found in the London Clay. 



182 MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 

IX. WETZELIELLA FROM THE LONDON CLAY 

By G. L. WILLIAMS & C. DOWNIE 

INTRODUCTION 

The characteristic Lower Tertiary genus Wetzeliella is among the commonest of the 
London Clay dinoflagellates. The excellent state of preservation has enabled its 
tabulation to be determined in many instances and its resemblance to the living 
genus Peridinium is established beyond doubt. Several new forms have been 
discovered and it is now possible to give a fuller description of some species already 
named. 

Genus WETZELIELLA Eisenack 1938 : 186 
Type species. Wetzeliella articulata Eisenack 1938. 

Emended diagnosis. Body with distinct pericoel and endocoel. Periphragm 
having a distinctive outline, varying from oval to pentagonal and generally prolonged 
into an apical horn, two lateral horns and one or two antapical horns. Periphragm 
may or may not bear intratabular processes. Processes (when present) open proxi- 
mally, open or closed distally and frequently arranged in process complexes. Endo- 
phragm circular to ovoid in outline, in cross section biconvex and separated, by 
pericoel of variable size from periphragm. Reflected tabulation of 4', 3a, 7", 5'", 
2"", 3-4S, ?c not always evident. Cingulum slightly laevo-rotatory, running round 
maximum width of periphragm. Sulcus wider and longer on hypotract than epitract. 
Archaeopyle usually present in periphragm and resulting from loss of plate 2a. 
Endophragm usually with archaeopyle in analogous position. 

Discussion. Wetzeliella is related to the living genus Peridinium, since it possesses 
identical tabulation and the same type of archaeopyle. It is distinguishable from 
Peridinium by the presence of usually well developed lateral horns, and in most cases 
by the numerous processes on the pericoel and the easily recognizable endocoel. 
Eisenack's (1964) placing of Wetzeliella and Deflandrea in a separate sub-order from 
Peridinium appears to be an artificial classification which disregards the evidence of 
tabulation. Dracodinium Gocht, 1955, is no longer recognized as a separate genus, 
since all stages of transition from Dracodinium solidum, the sole species of the genus, 
to Wetzeliella similis (Eisenack) occur in the London Clay. D. solidum (pars) is 
therefore placed in the genus Wetzeliella. Gocht's statement that the position of the 
slip hole (archaeopyle) is variable, prevents the complete incorporation of Draco- 
dinium solidum in Wetzeliella. Two sub-genera of Wetzeliella are recognized, 
Wetzeliella (Wetzeliella) Eisenack and Wetzeliella (Rhombodinium) (Gocht) Alberti, 
1961. 

The tabulation, which in many species is hard to determine, has been worked out 
for W. articulata, W. clathrata Eisenack, W. coleothrypta sp. no v., W. reticulata sp. nov. 
W. tenuivirgula sp. nov., W. homomorpha Deflandre & Cookson 1955, W. condylos sp. 
nov., and W. similis Eisenack 1954. In the sub-genus Wetzeliella (Rhombodinium) 
usually the only guide to tabulation is the archaeopyle. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 183 

Sub-genus Wetzelliella (Wetzelliella) Eisenack 1938. 

Diagnosis. A sub-genus of the genus Wetzeliella, possessing numerous processes 
developed from the periphragm. Processes showing only moderate variation in 
length and may be united distally. Processes intratabular, forming simulate 
complexes, or haphazardly distributed on plate. 

Type species. Wetzeliella [Wetzeliella) articulata Eisenack 1938. 

Wetzeliella (Wetzeliella) articulata Eisenack 
PI. 18, figs. 1-4 

1935. Peridinium sp., O. Wetzel : 168, pi. 2, fig. 1. 



1938. Wetzeliella articulata Eisenack 

1950. Wetzeliella articulata Eisenack 

1952. Wetzeliella articulata Eisenack 

1952. Wetzeliella articulata Eisenack 

I 953- Wetzeliella articulata Eisenack 

1954. Wetzeliella articulata Eisenack 

1956. Wetzeliella articulata Eisenack 

1959a. Wetzeliella articulata Eisenack 

1 961. Wetzeliella articulata Eisenack 

1 961. Wetzeliella articulata Eisenack 



186, text-fig. 4. 

Reissinger : 119, pi. 19, fig. 6. 

Gocht : 314, pi. 2, figs. 38, 39. 

Deflandre, text-fig. 89. 

Klumpp : 393, pi. 19. figs. 1-5. 

Eisenack : 55, pi. 7, figs. 1-11 ; pi. 8, figs. 14-16. 

Cookson : 185, pi. 2, fig. 6. 

Eisenack, pi. 3, fig. 7. 

Evitt : 397, pi. 8, figs. 3, 5, 6. 

Gerlach : 152, pi. 25, fig. 2. 



Discussion. W. (W) articulata is of widespread occurrence in the London Clay 
of Enborne and Sheppey but is uncommon at Whitecliff. The London Clay speci- 
mens do not vary from the type material. The tabulation has beeen worked out in a 
few individuals, from the alignment of some of the intratabular processes in simulate 
complexes. These are four apicals, three anterior intercalaries (of which plates ia 
and 3a are elongate) ; seven precingulars (with plates 2" and 6" elongate) ; 5 post- 
cingulars (all well developed plates) ; two antapicals of approximately equal size 
and three sulcals, with the posterior sulcal plate the largest. That the endophragm 
is subdivided into plates of similar orientation is suggested by the regularly ortho- 
gonal outline of the inner archaeopyle. 

Of the two antapical horns always present in W. (W) articulata the longer invari- 
ably lies to the right of the mid- ventral line, (for definition see Evitt 1963). The 
processes forming the simulate complexes lie just in from the plate boundaries. A 
few of the London Clay specimens have granular processes. Beautifully formed 
crystals of pyrite are found in the horns of some specimens but only rarely in the 
endocoel. 

Specimens intermediate to Wetzeliella symmetrica Weiler (1956) from the Oligo- 
cene of Germany, are not uncommon in the London Clay. These possess a reduced 
left antapical horn and/or an elongate apical horn, a length/breadth ratio of approxi- 
mately 1 to 1 and are probably synonymous with W. cf. symmetrica (Weiler) Maier 
(1959). Gerlach (1961) in a discussion of W. symmetrica symmetrica Weiler, 
mentions the occurrence of specimens with a second antapical horn. Unfortunately 
she did not figure any such types. 



184 MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 

Other individuals having a reduced apical horn and sometimes also a poorly 
developed left antapical horn are intermediate to W. similis Eisenack. These are of 
less frequent occurrence than the previously described forms. 

The forms recorded by Pastiels (1948) as Hystrichosphaeridium articulatum and 
transferred to W. articulata by Eisenack (1954), are not in fact representatives of this 
latter species. The diagnostic characteristics of W. articulata are the possession of a 
well developed apical horn and two well developed antapical horns, usually unequal 
in size. Pastiels' forms do not have this well developed second antapical horn and 
are transferred to W. (W) symmetrica var. lobisca (see p. 196). 

Dimensions. Observed range in London Clay : outer shell length iii-i62|x, 
breadth 64-105(1.. Number of specimens measured, 28. 

Occurrence. Eocene, London Clay ; Whitecliff, Studland, Sheppey and 
Enborne. W. articulata has been recorded in Europe from the Lower Eocene to the 
Middle Miocene. 

Wetzeliella (Wetzeliella) articulata var. conopia nov. 

PI. 18, fig. 5 

Derivation of name. Greek, konc-pos — gnat. 

Holotype. B.M.(N.H.) slide V. 51962. London Clay ; Sheppey, Kent, sample 
SL.4. 

Dimensions. Holotype : outer shell length 132^, breadth i26[x, Capsule length 
88[x. Observed range : outer shell, length i20-i56;x. Capsule, length 88-i05[i, 
breadth 83-92^. Number of specimens measured, 4. 

Description. A variety of W. (W). articulata having processes that distally may 
give rise to long aculei, often interconnected with aculei of adjacent processes. This 
is an intermediate form to W. (W). leptavirgula sp. nov. It has been found in the 
London Clay only at Sheppey. 

Wetzeliella (Wetzeliella) clathrata Eisenack 

PL 18, fig. 6 

1938. Wetzeliella clathrata Eisenack : 187, text-fig. 5. 

1954. Wetzeliella clathrata Eisenack ; Eisenack : 57, pi. 7, figs. 12-14 > text-fig. 2. 

1961. Wetzeliella clathrata Eisenack ; Gerlach : 153, pi. 25, fig. 6. 

1961. Wetzeliella clathrata Eisenack ; Evitt : 397, pi. 1, fig. 19. 

Discussion. A single specimen from the London Clay is attributed to W. (W). 
clathrata. Many individuals that on initial examination appear to belong to W. 
clathrata are really examples of W. (W). coleothrypta. W. clathrata is a distinctive 
species whose processes are aligned in rows, immediately within the boundary of 
a plate, forming simulate complexes. Adjacent processes are united distally by 
perforate membranes restricted in width to a few microns ; these are the " lists " of 
Eisenack. Tabulation is as in W. articulata and the reduced antapical horn lies to 
the left of the mid-ventral line. 



MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 



185 



Wetzeliella (Wetzeliella) coleothrypta sp. nov. 
PL 18, figs. 8, 9 ; Text-fig. 47 

Derivation of name. Greek, koleos, scabbard, sheath ; thrypto, break. 

Diagnosis. Thin walled periphragm characteristic pentagonal outline with each 
angle produced into horns, one apical, two lateral and two antapical ; left antapical 
horn generally reduced. Pericoel totally enclosing endophragm. Processes arising 
from periphragm, hollow, connecting with pericoel. Distally processes of individual 
simulate complex united by finely perforate membrane assuming outline of under- 
lying plate and extending over that plate as a replica of it. Processes commonly 
absent from pre- and postcingular plates on side lying nearest to cingulum. Reflec- 
ted tabulation of 4', 3a, 7", 5c, 5'", 2", 3-4S. 

Holotype. B.M.(N.H.) slide ¥.51753(3). London Clay ; Sheppey, Kent, 
sample Sh.4. 

Dimensions. Holotype : periphragm length \Z2\l ; breadth iiojx. Capsule 
length 6o.[x ; breadth 61-5(1. Observed range : outer shell length 1 12- 5-157^ ; 
breadth 102- 5-142^. Capsule length 66-106(1 ; breadth 67-97(1. Processes up to 
I5fx long. Number of specimens measured, 6. 

Description. The periphragm of W. coleothrypta has an outline approaching 
W. similis on the one hand and W. articulata on the other. The right antapical horn 
is invariably longer than the left, which is often represented by a small protuberance. 
The apical horn has a pointed apex ; the lateral horns are indented distally due to the 
transverse cingulum crossing from the dorsal to the ventral surface at these two 
places. The slender, simple, or occasionally branched processes are intratabular, 





Fig. 47. Wetzeliella (Wetzeliella) coleothrypta sp. nov. Left, tabulation of ventral (upper) 
surface of holotype ; right, tabulation of dorsal (lower) surface. S, sulcal plates ; PS, 
posterior sulcal plate ; stippled areas show where processes are united distally by a membrane. 



186 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

arising from just within the plate boundary and usually forming a simulate complex 
on each plate. The processes of each complex are united distally by a membrane 
which is finely perforate and which assumes the outline and area of the underlying 
plate. The general rule that the longer the processes, the further away they are 
from the horns, is found to be true for this species. 

The plates, interpreted from the simulate complexes, show considerable variation 
in size. Of the apicals, plate i' is by far the largest and has a trapezoid outline : 
plates 2' and 4' are lateral in position and are narrow, being represented by a single 
row of processes ; whilst the dorsal plate 3' is intermediate in size between 1' and 
4'. The anterior intercalary plates likewise vary in size and are dorsal in position. 
Plates ia and 3a are elongate, narrowing apically, whereas plate 2a, the loss of which 
forms the archaeopyle, is trapezoid, with processes absent from its equatorial boun- 
dary. The seven precingulars show extreme variation. Plates 1" and 7" are of 
comparable size with an almost triangular outline. Plates 2" and 6" are extremely 
narrow and are represented by a single row of processes running along the lateral 
margin. On the dorsal surface, the three plates 3", 4", and 5" are wider than the 
others and do not extend as far towards the apex, being restricted because of the 
anterior intercalaries. Plate 4" is the widest of the precingular series. 

The circular cingulum comprises five plates, three on the dorsal surface, two on the 
ventral. Each plate has a single row of processes that are united distally as in 
W. clathrata. Of the postcingulars, plates 1'" and 5'" on the ventral surface are of 
comparable size and shape (see Fig. 47), whilst plates 2'" and 4'" are smaller though 
of not dissimilar outline. The widest of the postcingulars is plate 3'", which usually 
has no processes on the side adjacent to the transverse cingulum. This is also 
frequently true of most of the pre- and postcingular plates. The two antapical 
plates are dorsally situated. The sulcus is considerably expanded on the hypo- 
tract and extends to the distal extremities of the antapical horns. There can be 
three or four sulcal plates, of which the most posterior is the largest and has a 
rhomboidal shape. Only one sulcal plate is present on the epitract. The tabulation 
is always clearly shown and easily decipherable. 

The width of the pericoel has no bearing on the thickness of the capsule wall, in 
this or any other species of Wetzeliella. Thin walled capsules often lie at a considerable 
distance from the periphragm. Evitt's (1961c) hypothesis that the greater the 
distance of the capsule from the enclosing periphragm, the thicker the endophragm, 
must therefore be applied with caution. The capsule of W. coleothrypta may be 
slightly granular ; it possesses an archaeopyle which is in line with that of the 
periphragm and appears to be intercalary. The operculum of the archeopyle is 
often found lying within the capsule. 

Remarks. Of the described species of Wetzeliella, only W. clathrata has processes 
united distally. However, whereas in W. clathrata the processes are united so as to 
give lists or bars of restricted width, in W. colethrypta, the membrane assumes the 
outline of the plate and passes completely over it, forming an outer umbrella. The 
two species can therefore be easily distinguished. 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 



187 



Wetzeliella (Wetzeliella) reticulata sp. no v. 

PI. 19, figs. 3, 6 ; Text-fig. 48 

Derivation of Name. Latin, reticulatus, netted, net-like. 

Diagnosis. Periphragm with distinctive pentagonal outline, produced into 
horns at each angle ; one apical, two lateral and two antapical horns. Right 
antapical always larger than left antapical horn. Periphragm totally enclosing 
ovoidal capsule. Surface of periphragm bearing intratabular processes, usually 
restricted to simulate complexes ; processes lying immediately within boundaries of 
plates. Processes diversely united within each complex by series of trabeculae, 
giving a reticulum extending over plate and assuming plate outline. Processes of 
adjacent plates not unified. Reflected tabulation 4', 3a, 7", 5c, 5'", 2"", 3 or 4s. 
Archaeopyle present. 

Holotype. B.M.(N.H.) slide ¥.51752(6). London Clay ; Sheppey, Kent, 
sample 2. 

Dimensions. Holotype : periphragm length 146^, breadth 162- 5[x, capsule 
length io6[x, breadth iiojj.. Observed range : outer shell length 146-167^, breadth 
150-162- 5[x. Capsule length i03-io6jx, breadth 95-1 iopi. Number of specimens 
measured, 2. 

Description. The shape and size of the plates of the periphragm of W. reticulata 
agree with those of W. coleothrypta (see previous description). The hollow, closed, 
cylindrical processes, in connection with the pericoel cavity are distally divided into 
numerous secae which ramify and are united by means of trabeculae with secae from 
processes of the same plate. The boundary of the reticulum thus formed is extremely 
regular, unconnected spines branching off only infrequently. Each reticulum 
mirrors the shape of the plate it overlies and is only slightly smaller. The trabeculae 
of the reticulum are taeniate. 





Fig. 48. Wetzeliella {Wetzeliella) reticulata sp. nov. Left, tabulation of the ventral (lower) 
surface of holotype ; right, tabulation of the dorsal (upper) surface. Stippling denotes area of 
simulate process complexes. The archaeopyle in the endophragm resulting from loss of plate 
2a is shaded. 



ISS 



MI.S07.0IC AND CAINOZOIC DI NOFL AGELL ATE CYSTS 



Processes can arise from any point on a plate within the simulate complex, some- 
times even forming secondary rows, further strengthening the reticulum. 

The capsule is large, almost filling the pericoel apart from the horns. It has a thin 
slightly granular wall. 

Occurrence. Eocene, London Clay ; Sheppey. 

Remarks. W. reticulata has an outline closely approaching W. articulata which 
can occasionally have processes that are united distally, but never in the form of a 
reticulum reflecting each individual plate constituting the pericoel. W. reticulata 
differs from W. coleothrypta in the distal structure of the processes and in having two 
well developed antapical horns. 

Wetzeliella (Wetzeliella) tenuivirgula sp. nov. 
PI. 19, figs. 2, 4 ; Text-fig. 49 

Derivation of name. Latin, tenuis, thinned ; virgula, small twig — referring to 
the processes. 

Diagnosis. Periphragm outline pentagonal to ovoidal, with each angle produced 
into a well developed tapering horn — one apical, two lateral and one or two antapical. 
Right antapical horn always the longer. Periphragm flattened in cross section, 
save medially where it encloses the ovoidal capsule. Hollow, slender or branched 
processes arising from periphragm and arranged in simulate complexes or occurring 
haphazardly within complexes. Processes terminating distally in elongate, solid 
secae, sometimes united to secae of adjacent processes ; giving rise to interconnec- 
tions between processes on opposite sides of plate or remaining unconnected. Tabu- 
lation typical of genus, with three sulcal plates. Archaeopyle usually formed. 




Fig. 49. Wetzeliella {Wetzeliella) tenuivirgula sp. nov. Left, tabulation of ventral (lower) 
surface of holotype ; right, tabulation of dorsal (upper) surface. Shading indicates archaeo- 
pyle. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 189 

Holotype. B.M.(N.H.) slide ¥.51964(2). London Clay ; Sheppey, Kent, 
sample 2. 

Dimensions. Periphragm, length 125-175(0. ; breadth 120-158(0.. Capsule, 
length, 72-113(0. ; breadth 70-104.fi.. Number of specimens measured, 9. 

Description. W. tenuivirgula commonly has an outline similar to that of 
W. articulata, with two well-developed antapical horns, although the left is absent in 
some individuals. The apical and antapical horns are acuminate distally ; the 
lateral horns are indented, denoting the position of a cingulum. The processes tend 
to be graded, being longest furthest away from the horns. 

Occurrence. Eocene, London Clay ; Sheppey and Enborne. 

In some specimens the majority of the processes are regularly arranged just within 
the plate boundary and form a simulate complex ; they may also arise nearer the 
plate centre. The secae, besides uniting adjacent processes, often extend across the 
plate, thus giving rise to a very loosely knit reticulum, totally different, in appear- 
ance to that found in W. reticulata. Unconnected acuminate spines, up to 2-3(0. in 
length, often arise from the interconnecting secae or trabeculae. The trabeculae 
may be granular or smooth ; the secae are usually extremely fine and regular. 
Processes of adjacent plates are not united. The pre- or postcingular plates may or 
may not have processes on the side nearest the cingulum. The capsule almost fills 
the pericoel, apart from the horns, and has a slightly granular wall. 

W. tenuivirgula differs from W. reticulata in the nature of the secae ; in the latter 
species these are short and complexly anastomosing and are rarely unconnected. 

Wetzeliella (Wetzeliella) tenuivirgula var. crassoramosa nov. 
PL 19, figs. 1, 5, 7 ; Text-fig. 50 

Derivation of name. Latin, crassus, thick, stout ; ramosus, branching ; 
hence thick-branched. 

Holotype. B.M.(N.H.) slide ¥.51954(2). London Clay ; Whitecliff, sample 
WC4. 

Dimensions. Holotype : outer shell length 125(0. ; breadth 122(0.. Capsule — 
length 8o[jl ; breadth 71 ;x. Observed range : outer shell length 125-182(1 ; breadth 
I22-i6o(ji. Capsule, length 80-144(0. ; breadth 71-103(0.. Number of specimens 
measured, 8. 

Description. This differs from the typical W. tenuivirgula in the nature of the 
distal branching of the processes ; the secae and trabeculae are much wider and 
taeniate, the reticulum being much stronger as a result. The processes forming the 
simulate complexes are often united by particularly wide taeniate secae (or bars) up 
to 3jjt. in width. Frequently there are simple unconnected spines with blunt or 
bulbous terminations branching off from the bars and trabeculae. In outline, the 
outer shell lies between that of W. articulata and W. symmetrica, individuals with 
an outline approaching the latter species predominating. 

Occurrence. Eocene, London Clay ; Whitecliff. 



igo 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Remarks. W. tenuavirgula var. crassoramosa does not merit raising to specific 
level, on account of the frequent occurrence of forms transitional to W. tenuovirgula. 
The extreme development of the secae (more correctly termed bars at this stage of 
development) however is very distinctive. 

Wetzeliella (Wetzeliella) homomorpha Deflandre & Cookson 

1948. Hystrichosphaeridium geometricum Pastiels (pars) : 41, pi. 4, figs. 3, 5, 6, 7, 9, 10. 
I 955- Wetzeliella homomorpha Deflandre & Cookson : 254, pi. 5, fig. 7 ; text-fig. 19. 

Discussion. The species W. homomorpha is restricted to forms having a peri- 
phragm with rhomboidal, ovoidal or sub-circular outline and which lacks well 
developed horns. The processes tend to be concentrated on the ambitus and are 
generally closed distally. The archaeopyle is intercalary. Deflandre & Cookson 
(1955) stated that none of the Australian examples contained the internal " cyst " 
characteristic of Wetzeliella. Their " cyst " formed by the endophragm is in fact 
present in the forms from the London Clay, but is easily overlooked, since it lies close 
to and follows the outline of the pericoel. W. homomorpha is therefore a species of 
Wetzeliella in which the periphragm and endophragm are almost in contact 
throughout. 




Fig. 50. Wetzeliella (Wetzeliella) tennivirgula var. crassoramosa nov. 
dorsal surface, showing simulate complexes. 



Tabulation of 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 191 

The processes of specimens of W. homomorpha from the London Clay are variable, 
simple or branched, single or in linear complexes, distally bifid, blunt or acuminate 
or with restricted opening. When open the processes have an entire margin. It is 
impossible to distinguish varieties of W. homomorpha on types of processes, since 
different types are often found on the same individual. The tabulation agrees with 
that for the genus, some of the processes closely following the plate boundary and 
almost being on it, others being well in from the margins. The number of processes 
per plate is variable. The lateral, apical and antapical areas can be marked by 
broad multibranched processes. 

Included within W. homomorpha are some of the forms described by Pastiels (1948) 
as Hystrichosphaeridium geometricum. Fuller discussion of the W. homomorpha/ 
H. geometricum complex will be found under W. homomorpha var. quinquelata. 



Wetzeliella (Wetzeliella) homomorpha var. quinquelata nov. 

PL 18, fig. 7 

1948. Hystrichosphaeridium geometricum Pastiels (pars) : 41, pi. 14, figs. 1, 2, 4, 8, 11. 
1961. Wetzeliella cf. oralis Eisenack ; Alberti : pi. 1, fig. 13. 

Derivation of name. Latin, quinque, five ; latus, side — hence, five-sided. 

Holotype. B.M.(N.H.) slide ¥.51963(1). London Clay ; Whitecliff, sample 
WC4. 

Dimensions. Holotype : periphragm, length 94[x ; breadth io5jx. Capsule, 
length 69^ ; breadth 69^. Observed range : outer shell, length (including horns 
and processes) 73—94(0., length (excluding horns and processes) 50-72^, breadth 
(including horns and processes) yy-io^\i, breadth (excluding horns and processes) 
53-70P1. Capsule, length 47-69^ ; breadth 50-69^. Length of processes 7. 
Number of specimens measured, 7. 

Description. This is a variety of W. homomorpha having a thin periphragm with 
a distinctly pentagonal outline. Each angle of the periphragm may be marked by a 
branched process, larger than the rest, or by a horn not exceeding 20(j, in length. 
When two antapical horns are present, the right is invariably the longer. The 
enclosed capsule has a pentagonal outline and is closely pressed against the peri- 
phragm save at the angles. The capsule wall is usually thin and smooth. 

The tabulation is often well shown from the orientation of the processes, which in 
some specimens are almost restricted to the plate boundary zone in simulate complex- 
es, whilst in others they are more numerous and irregularly arranged. The hollow, 
simple or branched processes tend to be concentrated on the ambitus of the peri- 
phragm. As in the typical W. Homomorpha, the processes show considerable 
variation distally. They are nearly always closed with acuminate, blunt or bifid tips, 
but several specimens with processes that open distally with aculeate or entire 



igj MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

margins are included since they are identical to W. homomorpha var. quinquelata in 
outline, wall thickness and tendency for processes to be concentrated on the ambitus. 
As is to be expected, intermediate forms exist between W. homomorpha and W. 
homomorpha var. quinquelata. 

Occurrence. Eocene, London Clay ; Whitecliff and Enborne. 

Stratigraphic range. W. homomorpha var. quinquelata has previously been 
recorded from the Ypresian of Belgium (Pastiels 1948) and the Upper Eocene of 
Germany (Alberti 1961). 

Remarks. Pastiels (1948) stated that H. geometricum is represented by flattened 
capsules, roughly pentagonal, of which one of the sides, sometimes concave, is 
smaller. Unfortunately the name created by Pastiels was pre-occupied by Hystri- 
chosphaeridium geometricum Deflandre 1942, for forms with a polygonal test from the 
Palaeozoic (since transferred to Veryhacium). This was pointed out by Deflandre & 
Cookson (1955), who in erecting W. homomorpha compared it to H. geometricum 
(Pastiels) and concluded that the two were probably synonymous. However, in the 
diagnosis of W. homomorpha, Deflandre & Cookson stated that the theca is polygonal, 
more or less rounded. A detailed study of London Clay forms attributable to the W. 
homomorpha-H. geometricum (Pastiels) complex has shown that there are two extreme 
forms of common occurrence, firstly pentagonal forms, often with well developed 
horns, and secondly ovoidal, sub-spherical or rhomboidal forms lacking horns. 
The two forms can be readily separated, although intermediate types do occur. 

Pastiels figured, as within his species, types identical to the two extreme London 
Clay forms, as well as intermediate specimens, although the holotype of H. geometri- 
cum (Pastiels) is almost pentagonal and the accompanying description suggests that 
specimens with a pentagonal outline were the more frequent in the Ypresian. It 
therefore seems advisable to restrict W. homomorpha to the forms having sub-spheri- 
cal, ovoidal or rhomboidal outline, whilst defining a variety, W. homomorpha var. 
quinquelata, to include forms having a pericoel with pentagonal outline with or without 
horns. This is a workable system in the London Clay and avoids too much infra- 
specific variation going unheeded. 

Wetzeliella (Wetzeliella) ovalis Eisenack 
PL 18, fig. 10 

1954. Wetzeliella ovalis Eisenack : 59, pi. 8, figs. 1-7. 

Discussion. The outline of the periphragm of London Clay specimens of W. 
ovalis is variable ; usually it is oval to rhomboidal, but it can be sub-pentagonal, 
with a fifth side tending to develop when there are two antapical horns. The angle 
of the sides are developed into small horns, one apical, two lateral and one or two 
antapical ; when there are two, the right antapical horn is always the longer. The 
simple or branched processes are intratabular and are uniformly present over all the 
surface of the pericoel, not as the type material where they are sparse on the dorsal 
and ventral surfaces. The tabulation of W. ovalis is the same as that of W. articulata. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 193 

The processes vary in width from 1-5-3^ ; they are in contact with the pericoel 
and are distally open, their margins being aculeate, with up to six aculei arising from 
a single process. The length of the aculei can be as great as 7jjl ; in some specimens 
they are granular. The nature of the processes distally is one of the diagnostic 
features of specimens of W. ovalis from the London Clay. 

The capsule almost completely fills the pericoel, sometimes even exhibiting a 
protuberance when opposite a horn. Its wall can be smooth or granular. An 
archaeopyle is commonly present. 

Dimensions. Range observed in London Clay : outer shell — length 94-120^, 
breadth jj-ii$[l. Capsule — length 68-79(1., breadth 67-78^. Number of specimens 
measured, 7. 

Occurrence. Eocene, London Clay ; Whitecliff and Enborne. 

Stratigraphic range. Present in the Oligocene of Germany (Eisenack 1954&) 
and in the London Clay. 

Wetzeliella (Wetzeliella) condylos sp. nov. 
PL 20, figs. 1, 2 

Derivation of name. Greek, kondylos, knuckle, knob, enlarged end of a bone : 
referring to the form of the processes. 

Diagnosis. Flattened outer shell with well formed lateral horns, low or absent 
apical horns and two antapical horns, the right one always longer. Apical area 
tending to be curved. Periphragm ornamented with a number of extremely short, 
blunt intratabular processes some arranged in simulate complexes reflecting a tabula- 
tion of 4', 3a, 7", xc, 5'", 2"", 3s, others occurring within complexes. Hypotract of 
periphagm of greater length than epitract. Capsule ovoidal to sub-circular in outline 
ellipsoidal in cross section. Endophragm up to yS\i thick, surface smooth or 
undulating. 

Holotype. B.M.(N.H.) slide V. 51967. London Clay ; Sheppey, Kent, sample 
Sh.2. 

Dimensions. Holotype : Periphragm, length i22[x, breadth ii2-5[x. Observed 
range : outer shell, length 76-i22[x, breadth 86-115^.. Capsule, length 56-85^ ; 
breadth 62-85^. Number of specimens measured, 6. 

Description. The periphragm of W. condylos is up to 3[x thick and forms the 
extremely small processes. These open to the pericoel and are cylindrical in cross 
section and distally closed with a blunt ending. The height of the processes is of the 
order of i-3[a. The characteristic generic tabulation can be determined from the 
regular disposition of the processes in simulate complexes on the pericoel. Auxiliary 
irregularly arranged processes are also common. The lateral horns of the peri- 
phragm are always prominently developed ; the apical horn, if present, is at the 
most a small protuberance. The capsule occasionally abutts on to the inner surface 
of the periphragm. 



194 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Occurrence. Eocene, London Clay ; Sheppey. 

Remarks. Only two described species of Wetzeliella, W. lineidentata Deflandre & 
Cookson, 1955 (Lower Tertiary, Australia) and W. irtyschensis Alberti, 1961 (Oligo- 
cene, U.S.S.R.) have processes of a similar nature to those of W. condylos. W. 
lineidentata was originally based on a single damaged specimen, the apical region of 
which was absent. Cookson & Eisenack (1961) however, discovered beautifully 
preserved complete specimens of this species from the Lower Tertiary of Western 
Australia. W. lineidentata differs from W. condylos in having lateral horns which 
arise in a medial position, a hypotract and epitract of similar size, the epitract of the 
outer shell having a triangular outline ; the capsule outline. The two species appear 
to be closely related however. W. irtyschensis differs from W. condylos in having 
poorly developed lateral horns and two antapical horns of equal length. 

Wetzeliella {Wetzeliella) similis Eisenack 
PL 20, fig. 5 

1954. Wetzeliella similis Eisenack : 58, pi. 8, figs. 8-10. 

1 961. Wetzeliella cf. similis Eisenack ; Gerlach : 154, pi. 25, fig. 5. 

Discussion. W. similis is interpreted from Eisenack's diagnosis, as a species of 
Wetzeliella having a broad low apical horn ; long, drawn out lateral horns ; and one 
antapical horn, which lies to the right of the midventral line, whilst to the left the 
other antapical horn is represented only by a low protuberance. The figures 
accompanying W. similis in Eisenack (1954) are unfortunately too poor to give any 
further help in recognition of the species, although one specimen he figured (pi. 8, 
fig. 9) has an apical opening and must be considered to belong to a genus other than 
Wetzeliella. 

W. similis is a species intermediate between W. articulata and W. solida (Gocht) 
(pars) Eisenack 1961, the former having a well developed apical and two antapical 
horns, the latter possessing only one well developed antapical horn, whilst an apical 
horn is absent. Attempts to set up a varietal name of W . similis for forms with very 
reduced apical horns have proved fruitless in the London Clay, intergradation being 
so gradual that it is impossible to distinguish any dividing line. It is therefore 
considered more advisable to extend the limits of W. similis to include forms with 
apical horns less than j\t. long. Forms with apical horns below 6[x would be placed 
in Wetzeliella solida. The apical horn of W. similis usually merges imperceptibly 
into the outline of the epitract ; it can occasionally be more sharply delimited. 
The single specimen described and figured by Gerlach (1961) is here included in 
Wetzeliella (W.) similis. 

Examples of Wetzeliella (W.) similis from the London Clay have an apical horn 
which is considerably broader and lower than that of W. articulata, whilst the 
indented lateral horns are long and drawn out. The right antapical horn is always 
longer than the apical horn. The left antapical horn is represented by a slight 
bulging of the pericoel. The breadth/length ratio of the outer shell generally 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 195 

exceeds 1 to 1. The slender, simple or branched processes are hollow, open distally 
with an aculeate margin, the aculei being patulate, orthogonal or even recurved. 
The processes reflect a tabulation agreeing with that of the type species W. articulata. 
The processes become shorter towards the horns. The periphragm can be up to 
i/2[x thick, and it is always smooth. 

The capsule is ovoidal or subcircular in outline, ellipsoidal in cross section. It lies 
at a variable distance from the inner surface of the periphragm, and has a wall up to 
2[x thick, which may be smooth or granular. Commonly observed in specimens of 
Wetzeliella (W.) similis is a local thickening of the endophragm directly opposite the 
point of origin of the horns. The significance of this may be that the horns are 
points of weakness within the cyst. 

Dimensions. Outer Shell, length ioo-i58[jl, breadth 117-166^. Capsule, length 
65-97 -5[x, breadth 66-g2\i. Length of processes 8-i8[x. Number of specimens 
measured, 15. 

Occurrence. Whitecliff and Enborne. 

Stratigraphic range. Oligocene of Germany (Eisenack 1954) and the London 
Clay. 



Wetzeliella (Wetzeliella) solida (Gocht) comb. nov. 

1955 Dracodinium solidum Gocht (pars) : 88-91, text-figs. 3a, b, 4a, b, 5a. 
1 961 Wetzeliella {Dracodinium) Solida (Gocht) Eisenack : 306. 

Discussion. Only a few specimens of W. Solida have been recorded from the 
London Clay. They are characterised by the absence of an apical horn. The 
surface of the periphragm bear slender, simple or branched processes that distally 
have an aculeate margin. The processes on the ambitus of the periphragm are often 
the shortest. The archeopyle is intercalary, the tabulation is the same as in other 
species of Wetzeliella with the apicals being reduced in size. 

Gocht (1955) erected the genus Dracodinium on the single species D. solidum and 
distinguished it from Wetzeliella on the absence of an apical horn. Within the 
species D. solidum he unfortunately included two distinct forms, those with inter- 
calary archeopyles and others with an apical archeopyle. Since the emended 
diagnosis of Wetzeliella excludes forms with an apical archeopyle, Gocht 's latter type 
needs transferring to a new genus, whilst the forms with the intercalary archeopyle 
are included within the genus Wetzeliella as W. solida. 

Dimensions. Periphragm, length io5-ii7(x, breadth 117 -5-137 y.. Capsule, 
length 68— 76^, breadth 69-82^. Number of specimens measured, 5. 

Occurrence. Whitecliff and Enborne. 

Stratigraphic range. W. solida has previously been recorded from the Eocene 
or Oligocene? of Germany (Gocht 1955). The forms classed as Dracodinium Solidum 
by Alberti (1961, pi. 1, fig. 9) appear to be another as yet unnamed species. 



196 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Wetzeliella (Wetzeliella) symmetrica Weiler 

PI. 20, fig. 6 

1956. Wetzeliella symmetrica Weiler : 132, pi. 11, figs. 1-3 ; text-figs. 2-5. 
1963. Wetzeliella symmetrica Weiler ; Brosius, pi. 2, fig. 7. 

Discussion. This species is characterized by a periphragm with rhomboidal 
outline, the angles of which are prolonged into more or less equally long horns. The 
single antapical horn sits astride the mid-ventral line. The processes commonly 
have aculeate distal margins or can be bifurcate. 

Dimensions. Range observed in London Clay : outer shell, length 125-167^, 
breadth n.5-148^. Capsule, length 70-97^, breadth 66-88[x. Number of speci- 
mens measured, 7. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne, Studland and Shep- 
pey. Wetzeliella (W .) symmetrica has also been recorded from the Oligocene of 
Germany (Weiler 1956, Alberti 1961, Gerlach 1961 and Brosius 1963). 



Wetzeliella (Wetzeliella) symmetrica var. lobisca nov. 
PI. 20, fig. 3 

1948. Hystrichosphaeridium articulatum Pastiels : 43, pi. 4, figs. 13, 17. 
1961. Wetzeliella symmetrica symmetrica Gerlach : 185, pi. 25, figs. 7, 8. 

Derivation of name. Latin ; lobisca, a small protuberance. 

Holotype. B.M.(N.H.) slide V.51970. London Clay ; Sheppey, Kent, sample 
1. 

Dimensions. Holotype : outer shell, length 13711, breadth I23fx. Capsule, length 
j8[i, breadth yo\x. Observed range : outer shell, length I25-I37fi., breadth, 118- 
I50pt. Capsule, length 72-80^, breadth 70-79^. Number of specimen, measured, 4. 

Description. This is a variety of W. (W.) symmetrica which has a slightly 
reduced apical horn and the single antapical horn is offset to the right of the mid- 
ventral line. It is identical with the two figured specimens of W. symmetrica 
symmetrica Gerlach (1961) and Hystrichosphaeridium articulatum Pastiels (1948). 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne and Sheppey. It has 
also been recorded from the Ypresian of Belgium (Pastiels 1948 as H. articulatum) 
and the Oligocene-Miocene of Germany (Gerlach 1961). 

Wetzeliella (Wetzeliella) varielongituda sp. nov. 
PI. 20, figs. 4, 8 

Derivation of name. Latin ; varius, varied, longituda, length. 

Diagnosis. Periphragm outline sub-rhomboidal, with short broad lateral horns, 
a short wide apical horn and one well developed (right) antapical horn. Left 



MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 197 

antapical horn represented by slight protuberance on left antapical margin. Cap- 
sule thick walled, often coarsely granular. Processes extremely short on ambitus of 
periphragm and increasing in length further away from ambitus. Distally processes 
bifid, aculeate, acuminate or evexate. 

Holotype. B.M.(N.H.) slide V. 51973. London Clay ; Sheppey, Kent, sample 2. 

Dimensions. Holotype : outer shell, length i03[x, breadth ioof*. Capsule, 
length 73[x, breadth 7ijjl Observed range : outer shell, length o,6-i26[x, breadth 
90-i25[x. Capsule, length 64-79^, breadth 63-84^. Length/breadth ratio of 
pericoel 1-1 to i-i-i. Number of specimens measured, 7. 

Description. One of the diagnostic features of W. varielongituda are the processes. 
The wall of the periphragm is up to i/2(jl in thickness, so that the slender processes 
have only a minute central tubule, along their length. They are distally closed, 
proximally open to the pericoel. The processes can be granular and are always 
simple. The shortest processes occur on the ambitus of the pericoel and particularly 
is this so on the lateral horns and epitract. It is these processes that can be acumin- 
ate or evexate distally. The processes are regularly orientated in simulate complexes 
or are irregular occurring within the complexes. Typical Wetzeliella tabulation is 
decipherable, with the archeopyle intercalary. 

The horns of W. varielongituda tend to be broad and low, merging imperceptibly 
with the lateral margins of the periphragm. This is especially so with the apical 
horn. 

The capsule is sub-circular in outline, ellipsoidal in cross section and has a wall up 
to 3*5{x thick. The wall often shows local thickening directly opposite the horns. 
Distance of the capsule from the inner surface of the periphragm is variable. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. 

Remarks. The nature of the processes, outline of the pericoel and structure of the 
capsule readily distinguish Wetzeliella (W.) varielongituda from other species of 
Wetzeliella. 

Sub-Genus WETZELIELLA (RHOMBODINIUM) Gocht 1955 

Diagnosis. A sub-genus of the genus Wetzeliella that does not possess processes 
on the periphragm. Tabulation indistinctly shown apart from a transverse cingulum. 

Type species. Wetzeliella (Rhombodinium) draco (Gocht 1955). Oligocene ; 
Germany. 

Wetzeliella (Rhombodinium) glabra Cookson 

PI. 20, figs. 9, 10 

1956. Wetzeliella glabra Cookson : 186, pi. 2, figs. 1-5. 

Discussion. Specimens of W. glabra from the London Clay differ from the type 
material in having only one well developed antapical horn, the right. The left 
antapical horn is, at the most, represented by a slight protuberance. The transverse 



i 9 8 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

girdle is also less well marked whilst the capsule archaeopyle gives the impression of 
being apical in some specimens. This may be due to secondary movement of the 
capsule within the pericoel. The capsule is occasionally found free. 

On the outer surface of the periphragm of some individuals are present dendritic 
ridges, radiating out from central points and being up to 10 or 15^ across. They are 
not caused by local thickenings of the wall but by undulations. On an individual 
there can be a large number of these dendritic radiating structures. They are 
possibly a result of fungal attack. W. glabra is included in the sub-genus Rhombo- 
dinium on account of the absence of processes. 

Dimensions. Range observed in London Clay : outer shell, length i^o-i^i\i, 
breadth 147-168^. Capsule, length 66-8o[i, breadth 69-76^. Number of speci- 
mens measured, 6. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. Eocene ; Australia 
(Cookson 1956). 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 199 

X. FURTHER DINOFLAGELLATE CYSTS FROM THE SPEETON CLAY 

By W. A. S. SARJEANT 

INTRODUCTION 

The assemblages of dinoflagellate cysts from the Speeton Clay are both extremely 
rich and extremely varied. Their description was begun in a previously published 
paper (Neale & Sarjeant 1962) and a number of species are here dealt with, wherever 
appropriate, in earlier chapters. All remaining species represented that have been 
studied to date are described in this chapter, and the stratigraphical distribution of 
all the constituent species of the assemblages is summarized in tabular form and 
discussed. 



Genus NETR ELYTRON Sarjeant 1961a : 113 

Emended diagnosis. Cavate dinoflagellate cysts, enclosing body spindle-shaped, 
inner body ovoidal to spindle-shaped. Shell showing no trace of tabulation or of 
cingulum or sulcus. Shell enclosed in cloak of adherent organic matter, formless or 
oval to spindle-shaped in outline : fragments of mineral matter and other sediment- 
ary debris sometimes embedded in cloak. Archaeopyle frequently developed : 
precingular in position. 

Type species. Netrelytron stegastum Sarjeant 1961a. Upper Jurassic (Oxford- 
ian) ; England. 

Remarks. This genus is characterized by its shape, cavate character and invest- 
ing mass of organic matter ; formation of a similar debris cloak during encystment 
is known to occur in some modern dinoflagellates. 

The genus Kalyptea Cookson & Eisenack 19606 from the Upper Jurassic of Austra- 
lia, is described as having a " diaphanous veil-like external membrane ", which may 
correspond to the organic cloak of Netrelytron ; the cysts are oval, with one to two 
horns, but lack an inner body. The somewhat similar genus Koniewuia Cookson & 
Eisenack 1960&, also from the Upper Jurassic of Australia, lacks either outer cloak or 
inner body. 



Netrelytron trinetron sp. nov. 
PL 22, fig. 3 ; Text-fig. 51 

Derivation of name. Greek, tri-, three ; netron, spindle : referring to the 
similar shapes of the debris cloak and the enclosing and inner bodies. 

Diagnosis. A Netrelytron with outer body of basically ovoidal shape, giving rise 
to strongly tapering, conical apical horn and somewhat shorter, conical antapical 
horn. Shape of inner body exactly similar. Horns polar and axial in position and 
direction. Endophragm and periphragm minutely, but densely, granular. 



200 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Holotype. B.M.(N.H.) slide ¥.51729(1). Speeton Clay, Shell West Heslerton 
Borehole at 39 metres depth, West Heslerton, Yorks. Lower Cretaceous (Middle 
Barremian). 

Dimensions. Holotype — overall length of enclosing body go[i, breadth 53— 5[x, 
length of apical horn i8[i., of antapical horn 5[x ; overall length of inner body 67-5^1, 
breadth 38-5[x. Range of dimensions ; overall length of enclosing body c. 70-95^. 

Description. The holotype is enclosed in a spindle-shaped cloak of debris : in 
other specimens, the debris cloak appears less well formed. 

The outer membrane is spindle-shaped, with unequally developed horns. In the 
holotype, the apical horn tapers sharply to an acute point from about mid-length : 
this was not the case in other specimens, where the apical horn tapered more smoothly 
from base to tip. The inner body is of comparable shape, its apical horn always 
tapering smoothly from base to tip. 

No specimen seen shows a well-developed archaeopyle ; however, the holotype 
shows a slit, corresponding in position to a precingular opening, which may be an 
archaeopyle that has either incompletely opened or subsequently closed up. 




Fig. 51. Netrelytron trinetron sp. nov., showing the shell surrounded by the 
enclosing cloak of organic matter. x c. 500. 



MESOZOIC AND CAINOZOIC DI NOFL AGELLATE CYSTS 201 

Remarks. In the form of the inner body, Netrelytron trinetron sp. nov. differs 
from both other described species of the genus. It has only been recorded to date 
from one horizon in the West Heslerton Bore, from which some six specimens have 
been recorded. 



OTHER SPECTES 

Netrelytron jurassicum (Alberti 1961) from the Middle Jurassic (Bathonian-Callo- 
vian) of Germany, is here transferred to this genus from Kalyptea on the basis of its 
possession of an inner body within the spindle-shaped shell. 

Brosius (1963 : 38, pi. 3, fig. 2, pi. 4, fig. 2, pi. 5, fig. 4) has described a species 
from the German Oligocene, as Netrelytron sp. nov. This corresponds in most 
particulars to the emended diagnosis of Netrelytron, but lacks a cloak of debris. 
Erection to separate generic status may prove appropriate. 



Genus PARANETRELYTRON nov. 

Derivation of name. Greek, para, near ; netron, spindle ; elytron, sheath, 
husk — refers to the similarity of this genus to Netrelytron. 

Diagnosis. Cavate dinoflagellate cysts, enclosing body spheroidal to ovoidal 
with apical horn ; inner body spheroidal. Shell lacking tabulation, with or without 
traces of cingulum. Shell enclosed in cloak of adherent matter, formless to oval in 
outline ; fragments of mineral matter and other sedimentary debris sometimes 
embedded in cloak. Archaeopyle formation not known. 

Type species. Paranetr elytron strongylum sp. nov. Lower Cretaceous (Lower 
Barremian) ; England. 

Remarks. This genus differs from Netrelytron in lack of an antapical horn and in 
presence of indications of a cingulum ; and from all other described genera in the 
possession of an outer cloak of organic debris. 



Paranetrelytron strongylum sp. nov. 
PL 21, fig. 5 ; PI. 23, fig. 5 ; Text-fig. 52 

Derivation of name. Greek, strongylos, round, rounded. 

Diagnosis. A Paranetrelyton having a spheroidal outer body tapering smoothly 
to form short, blunt apical horn. Inner body spheroidal and relatively large, 
thin-walled and often hard to distinguish. A poorly-marked cingulum sometimes 
present. Endophragm and periphragm smooth or only very minutely granular. 

Holotype. B.M.(N.LL) slide 51722(1). Speeton Clay, Shell West Heslerton 
Borehole at 42-5 metres depth, West Heslerton, Yorks. Lower Cretaceous (Lower 
Barremian). 



202 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Holotype : overall length 56(1, breadth 45^, length of apical horn 
iopi ; length of inner body 0.40(1, breadth 0.40(1.. Range of dimensions : overall 
lengths 51-58^ 

Description. The holotype is enclosed in a roughly oval cloak of debris ; in the 
three other specimens observed to date, the debris cloak was comparable. The 
enclosing body is roughly lemon-shaped. The inner body fits quite closely, except at 
the apical end where there is a quite large expansion of the pericoel. It is thin and 
transparent and, as a result, very hard to distinguish ; its presence was confirmed 
only under phase contrast. 

The debris cloak of the holotype contains a ball-like mass of debris immediately 
posterior to the antapex. This structure is of doubtful significance and may simply 
represent fortuitous adherence of organic debris from a quite unrelated source. 
An archaeopyle has not been observed to date. 

Remarks. Paranetr elytron strongylum sp. nov. occurs in the 39 and 42-5 metres 
horizons in the West Heslerton Borehole (Lower to Middle Barremian). Its small 
size and debris cloak render it especially inconspicuous ; further studies may well 
indicate a much wider distribution. 

Genus MUDERONGIA Cookson & Eisenack 1958 : 40 

Type species. M. mcwhaei Cookson & Eisenack 1958. Lower Cretaceous 
(Aptian) ; Australia. 



(A ;A^ 




Fig. 52. Paranetr elytron strongylum sp. nov., showing the shell surrounded by 
the enclosing cloak of organic matter. x c. 750. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 203 

Muderongia staurota sp. nov. 
PL 21, figs. 6, 7 ; PL 23, fig. 4 ; Text-fig. 53 

Derivation of name. Greek, staurotos, cruciform. 

Diagnosis. A Muderongia having an ovoidal to ellipsoidal enclosing body, 
prolonged into four strong horns. Apical horn strong and tapering, length slightly 
less than length of shell alone. Lateral horns quite short, less than shell breadth, 
at first almost parallel sided, but at about one-third length, anterior margin tapering 
backward to form an angle with posterior margin. Antapical horn basically conical, 
with slight out-bulge at one side ; length also less than length of shell alone. Inner 
body ovoidal to ellipsoidal. Periphragm smooth or finely pitted ; endophragm 
varying from smooth to densely granular. Shell showing neither trace of tabulation 
nor of cingulum or sulcus. An apical archaeopyle is formed. 

Holotype. B.M.(N.H.) slide ¥.51724(3). Speeton Clay, Shell West Heslerton 
Borehole at 42-50 metres depth, West Heslerton, Yorkshire. Lower Cretaceous 
(Lower Barremian). 

Paratype. B.M.(N.LL) slide ¥.51718(3). Same locality and horizon. 




Fig. 53. Muderongia staurota sp. nov. Left, holotype. Right, paratype. The variation 
in proportions and in degree of granularity of the inner body is shown : the holotype 
shows incipient formation of an archaeopyle. x c. 500. 



2o 4 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Holotype — overall length 170^, breadth 93(0. ; length of apical 
horn (tip missing) 55^, of antapical horn 34-5[i., of longer lateral horns 26^, length of 
inner body, yoy., breadth 55^. Paratype — overall length 145(1, breadth 8oji. ; 
length of apical horn, 47(x, of antapical horn, c.44^, of longer lateral horns c.3i[x ; 
length of inner body c.^6[i, breadth c.5i[i.. These two specimens represent opposite 
extremes of the observed range of variation. 

Description. The enclosing body has a basically cruciform outline, with a 
distinctly oval shell enclosing, more or less tightly, an inner body of similar shape. 
The lateral horns show no distinct notch, nor is a second, shorter antapical horn 
developed ; however, the backward curve of the lateral horns and the lateral bump 
on the antapical horn suggest affinity to species showing these features. 

The periphragm shows some degree of pitting, variable in degree and location but 
usually especially dense on the apical horn. The inner body varies from smooth to 
granular ; where it is smooth, the inner body becomes hard to distinguish and may 
only be confirmed under phase contrast. (The holotype and paratype illustrate this 
variation.) 

This species is relatively common in the Lower Barremian of the West Heslerton 
Borehole : over 20 specimens were noted, of which the majority comprised either 
detached apices or shells lacking an apex, complete shells being relatively infrequent. 
Both holotype and paratype show incipient development of an archaeopyle. 

Remarks. Muderongia staurota sp. nov. is characterized by the morphology of its 
shell processes. In contrast M. mcwhaei has a pronouncedly rhombic shell outline ; 
proportionately longer and slimmer horns ; notched lateral horns and a second, short 
antapical horn. M. simplex Alberti 1961, from the Lower Cretaceous (Hauterivian 
to Valanginian) of Germany and Bulgaria, has short horns of almost equivalent 
relative length, the lateral horns being blunt and notched, and a second antapical 
horn being again developed. M. perforata Alberti 1961, from the Upper Cretaceous 
(Turanian) of Germany, has very strong, thick horns, the second antapical horn 
being especially pronounced. M. tetracantha (Gocht 1957), from the Lower Cretace- 
ous (Hauterivian) of Germany, has in contrast extremely long and delicate horns ; 
a second antapical horn is lacking, but the notching of the lateral horns is so deep asto 
approach bifurcation into unequal branches. M. tomaszowensis Alberti 1961, from 
the Lower Cretaceous (Valanginian) of Germany and Poland, has stubby apical and 
antapical horns and blunt notched lateral horns. M. cruets Neale & Sarjeant 1962, 
from the Lower Cretaceous (Hauterivian) of England, is extremely large (overall 
length 250-325^) , with long axial horns and long lateral horns, the latter backswept 
and not notched. 



Genus APTEODINIUM Eisenack 1958c 

Type species. A. granulatum Eisenack 1958c. Lower Cretaceous (Aptian) ; 
Germany. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



205 



Apteodinium maculatum Eisenack & Cookson 
PL 22, fig. i ; Text-fig. 54 

i960. Apteodinium. maculatum Cookson & Eisenack : 4, pi. 2, figs. 1-3. 

Remarks. This species, hitherto recorded only from the Lower Cretaceous (Aptian 
to Albian) of Australia, occurs in low numbers in the assemblages from the Shell 
West Heslerton Borehole, West Heslerton, Yorkshire, at 42-50 metres depth. 
(Lower Barremian). 

The English specimens are somewhat smaller than the Australian type material : 
the figured specimen (B.M.(N.H.) slide ¥.51718(4)), with overall length 75[x, breadth 
64^, falls a little below the quoted Australian range of length 74-105^, breadth 
70-105(1. There are faint indications of a sulcus and the " small thickened areas with 
circular outlines " noted by Eisenack and Cookson are totally lacking. Nor has an 
archaeopyle been observed to date. (The " hoof-shaped pylome " mentioned by 
those authors must be interpreted as a precingular archaeopyle.) However, the 
triviality of these differences and the complete correspondence in other characters 
does not justify any nomenclatural distinction of the English specimens, which 
accordingly represent a considerable extension in the geographic and stratigraphic 
range of this species. 

Genus DOIDYX nov. 

Derivation of name. Greek, doidyx, pestle, in reference to the shell shape. 

Diagnosis. Proximate dinoflagellate cysts with flattened biconical shell, pro- 
nouncedly asymmetical. Epitract in form of high cone which may be drawn out 
into an apical horn, giving a mammillate appearance : hypotract in form of flattened 
cone, with or without antapical prominence. Shell bulging out laterally to one side 
more than to the other ; lateral horns lacking. Greater part of shell surface covered 





Fig. 54. Apteodinium maculatum Eisenack & Cookson, showing the dense granulosity 
and the positions of cingulum and sulcus. x c. 800. 



206 MKSOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

with short spines, simple or bifurcate : arrangement is in general random, but 
sometimes in rows, suggesting traces of tabulation. Equatorial zone, corresponding 
to cingulum, lacking spines : not hollowed. No pattern of sutures visible, no clear 
indication of sulcus. Apical archaeopyle formed by schism of shell on angular line 
of breakage. 

Type species. Doidyx anaphrissa sp. now Lower Cretaceous (Lower Barre- 
mian) ; England. 

Remarks. In its asymmetrically biconical shell, spine cover and absence of 
tabulation, this new genus differs from all described fossil genera. The asymmetry 
and mode of archaeopyle formation suggests a probable derivation from the genus 
Pseitdoceratium by reduction of polar horns and loss of the lateral horn. 

Doidyx differs from Diconodinium, Palaeohystrichophora and Dioxya in its asym- 
metrical shape : from Diconodinium also in the absence of a sulcus : from Palaeo- 
hystrichophora also in the lack of an inner body ; and from Dioxya in the clear 
indication of a cingulum. It differs from the superficially similar genus Aptea in the 
lack of an enclosing membrane. 

Doidyx anaphrissa sp. nov. 
PL 22, fig. 8 ; PI. 23, fig. 6 ; Text-fig. 55 

Derivation of name. Greek, anaphrisso, to bristle. 

Diagnosis. A Doidyx having an asymmetrically biconical shell with short, 
blunt apical horn and with low bump on antapex. Spines simple, capitate or briefly 
bifurcate. Portion thrown off in archaeopyle formation exceeding one-third of shell 
length. 




Fig. 55. Doidyx anaphrissa sp. nov. Holotype, 
showing archaeopyle formation. x c. 750. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 207 

Holotype. B.M.(N.H.) slide ^^.51723(3). Speeton Clay, Shell West Heslerton 
Borehole, West Heslerton, Yorks., at 42-5 metres depth. Lower Cretaceous (Lower 
Barremian) . 

Dimensions. Holotype — overall length io5[x, breadth ii8[jl ; shell length iijjl, 
breadth io2[x ; spines c.jy. long. Range of dimensions : overall lengths c.i20-i45(x, 
breadths c.io5-i30fx. 

Description. This species is moderately abundant, some 25 specimens having 
been encountered ; complete shells were infrequent, detached apices and shells 
lacking an apex being commoner. 

The shell is approximately club-shaped : its asymmetry is so pronounced that a 
longitudinal division would leave some 60% on one side, some 40% on the other. 
The epitract slopes smoothly into the apical horn ; the hypotract is surmounted by an 
antapical bulge of small height and larger amplitude. The surface is very minutely 
granular. 

There is a dense cover of short spines, most often capitate, less frequently evexate, 
oblate, bifid or bifurcate : these sometimes suggest arrangement into lines, but no 
coherent pattern was determined. An equatorial belt of moderate breadth, corres- 
ponding to the cingulum, lacks spines : a sulcus is not distinguishable. 

The holotype shows fission to form an archaeopyle, which has however, not 
become detached. Its margin is distinctly angular, suggesting a tabulation pattern 
not otherwise indicated. 

Remarks. In its combination of shape, process cover and mode of archaeopyle 
formation, Doidyx anaphrissa sp. nov. differs from all other described species. 



Genus BROOMEA Cookson & Eisenack 1958 : 41 

Type species. B. ramosa Cookson & Eisenack 1958. Middle-Upper Jurassic ; 
Australia. 



}Broomea longicornuta Alberti 
PL 21, fig. 1 

1961. IBroomea longicornuta Alberti : 27, pi. 5, figs. 18-21, pi. 6, figs. 1, 2. 

Remarks. This species, originally described from the Lower Cretaceous (Hauteri- 
vian-Upper Barremian) of Germany, is represented by a single specimen in the 
assemblage from the Speeton Clay of the West Heslerton Borehole at 19- 25 metres 
depth (Upper Barremian). The dimensions of this specimen, B.M.(N.H.) slide 
V. 51733(1), are overall length c.285^ ; shell length ioofj., breadth 480. ; length of 
apical horn c.i30[x ; length of unbent antapical horn 55^. This falls within the 
range of overall lengths quoted by Alberti (248-298^). 



2oS MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Genus ODONTOCHITINA Deflandre 1935a : 234 

Type species. Ceratium (Euceratium) operculatum O. Wetzel 1933. Upper 
Cretaceous ; Germany. 



Odontochitina operculata (O. Wetzel) 

PL 21, fig. 2 

1933. Ceratium {Euceratium) operculatum O. Wetzel : 170, pi. 11, figs. 21-22. 

I 935- Odontochitina silicorum Deflandre : 234, pi. 10, figs. 8-10. 

1937. Odontochitina silicorum Deflandre ; Deflandre : 47, pi. 18, figs. 8-10. 

1946. Odontochitina operculata (O. Wetzel) Deflandre, cards 1016-19. 

1948. Palaeoceratium operculatum (O. Wetzel) O. Wetzel : ?342. 

1950. Dreihornige Hullen mit Stachelkleid, O. Wetzel : 170, pi. 13, fig. 6. 

1952. Odontochitina operculatum (O. Wetzel) ; Firtion : 160, pi. 8, fig. 9. 

1955. Odontochitina operculata (O. Wetzel) ; Deflandre & Cookson : 291, pi. 3, figs. 5, 6. 

1955. Odontochitina operculata (O. Wetzel) ; Deflandre-Rigaud : 19. 

1955. Odontochitina operculata (O. Wetzel) ; Valensi : 594, pi. 4, fig. 7. 

1958. Odontochitina operculata (O. Wetzel) ; Eisenack : 393, pi. 27, figs. 7, 8. 

J 959- Odontochitina operculata (O. Wetzel) ; Gocht : 64, pi. 6, fig. 12. 

1 961. Odontochitina operculata (O. Wetzel) ; Alberti : 30, pi. 6, figs. 6-9. 

1961. Odontochitina operculata (O. Wetzel) ; Eisenack : 323, pi. 36, fig. 3. 

1962. Odontochitina silicorum Deflandre ; Pocock : 78, pi. 14, figs. 211, 212. 

1963. Odontochitina operculata (O. Wetzel) ; Gorka : 35, pi. 4, figs. 1-5. 

1963. Odontochitina operculata (O. Wetzel) ; Baltes : 584, pi. 5, figs. 1-4. 

1964. Odontochitina operculato (O. Wetzel) ; Singh : 147, pi. 20, figs. 9, 10. 

Remarks. This species is long-ranging and widespread : it has been recorded 
from the Upper Jurassic of Canada by Pocock (1962) and has a well-documented 
range in the Cretaceous, from Upper Hauterivian to Campanian. It is present in low 
numbers in the assemblages from 19-25 metres depth in the Shell West Heslerton 
Borehole (Upper Barremian). All specimens seen lacked the apex ; the figured 
specimen, B.M.(N.H.) slide ¥.51730(4), is the best-preserved, having an overall 
length of 133-5^, breadth 88[x, the central body being 53^ long and 48^ broad, the 
lateral horn c.55[jl long and the antapical horn 83'5fx long. The range in dimensions 
observed was overall lengths 120-133- 5[x, breadths 67-100(0. : these fall well within 
the previously quoted ranges. Detached horns, probably of 0. operculata, were also 
observed. 

Odontochitina operculata is also present at all levels in the Cenomanian of the H.M. 
Geological Survey Borehole at Fetcham Mill, Surrey. 



Genus FROMEA Cookson & Eisenack 1958 : 55 

Type species. Fromea amphora Cookson & Eisenack 1958. Cretaceous (Aptian 
to Cenomanian) ; Australia. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 209 

Fromea amphora Cookson & Eisenack 
PL 22, fig. 4 ; PL 23, fig. 3 

1958. Fromea amphora Cookson & Eisenack : 56, pi. 5, figs. 10, 11. 
1961. Fromea amphora Cookson & Eisenack ; Alberti : 23, pi. 12, fig. 13. 
?ig6i. Chrysomonadiniae? Maliavkina et al., pi. 52, figs. 1-5. 

Remarks. This species, originally described from somewhat higher horizons in 
Australia, has been recorded by Alberti from the Upper Barremian of Germany and 
occurs at this level in the Shell West Heslerton Borehole (at 19-25 metres depth). 
The figured specimens, B.M.(N.H.) slide ¥.51732(1, 2), are of closely similar size, 
respectively measuring 84 x 49fx and 84 x 50[x, the apex being lacking ; this is 
within the range quoted for the Australian specimens (62-95^ x 47-81^) and larger 
than that quoted for the German specimens (58-66(1, x 49-52(1) . 

The shell surface is minutely granular in these specimens ; there is little indication 
of a cingulum. 

The specimens figured by Maliavkina et al. (1961, pi. 52, figs. 1-5), from the 
Maestrichtian of Siberia, may be examples of Fromea amphora, but are rather small. 



Genus SYSTEMATOPHORA Element i960 : 61 

Type species. S. areolata Klement i960. Upper Jurassic (Kimmeridgian) ; 
Germany. 

Systematophora schindewolfi (Alberti) 
PL 22, fig. 5 

1 961. Hystrichosphaerina schindewolfi Alberti : 38, pi. 10, figs. 1-3, 6, 7. 

1962. Systematophora schindewolfi (Alberti) Neale & Sarjeant : 455 (by implication). 

Remarks. This species, originally described from the Cretaceous (Upper Bar- 
remian to PSenonian) of Germany, has been encountered only in the horizon from 
42-5 metres depth in the Shell West Heslerton Borehole (Middle Barremian). The 
majority of examples are too obscured or badly positioned for study, but one 
specimen, B.M.(N.H.) slide V. 517121(1), was excellently preserved and favourably 
orientated. Its dimensions (overall length 1200., breadth ii2fji ; shell length 65jx, 
breadth 6o[j.) accord with those quoted by Alberti (shell length 58-70(1 ; length of 
appendages 22-39(1). 

Study showed that the distribution of the annular process complexes on epitract 
and hypotract, and the linear equatorial complexes, was precisely that specified for 
the genus by Klement. 

Genus GARDODINIUM Alberti 1961 : 18 

Type species. Gardodinium eisenacki Alberti 1961. Lower Cretaceous (L. 
Hauterivian to Aptian) ; Germany. 



->io MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Gardodiniutn eisenacki Alberti 

PI. 21, fig. 4 

1961. Gardodinium eisenacki Alberti : 18, pi. 3, figs. 8-13. 

Remarks. This species occurs in moderate abundance in the assemblages from 
39 metres and 42-5 metres depth. Specimens are frequently distorted. The 
figured specimen, B.M.(N.H.) slide ¥.51726(1), is the best preserved ; its dimensions 
are overall length j6\x, breadth 55^ ; shell length 56(0., breadth 50;x. The range of 
dimensions exhibited accords closely with that quoted by Alberti (77-85(0 x 55-60(0 
overall). 

Genus DINGODINIUM Cookson & Eisenack 1958 : 39 

Type species. Dingodinium jurassicum Cookson & Eisenack 1958. Upper 
Jurassic ; Papua and Australia. 

} Dingodinium albertii sp. nov. 

PL 21, fig. 3, PL 23, fig. 1 

1961. Dingodinium sp. A., Alberti : 17, pi. 3, fig. 16. 

Derivation of name. Named in honour of Dr. Gerhard Alberti, the first to 
describe this form of cyst. 

Diagnosis. A cavate dinoflagellate cyst with thin outer shell, irregularly ovoidal 
to subpolygonal in outline, drawn out into a blunt, stout apical horn ; inner body 
thin, spheroidal, with dense cover of large, pointed tubercles. Outer shell posses- 
sing clear helicoid cingulum marked by prominent folds or ridges ; further folds or 
ridges, less prominent, define tabulation. Intercalary archaeopyle apparently 
formed. 

Holotype. B.M.(N.H.) slide ¥.51719(2). Speeton Clay, Shell West Heslerton 
boring at 42-50 metres depth, West Heslerton, Yorks. Lower Cretaceous (Lower 
Barremian). 

Paratype. B.M.(N.LL) slide ¥.51723(1). Same locality and horizon. 

Dimensions. Holotype — overall length 66[i, breadth 52^, length of inner body 
40jjl, breadth 45^. Paratype — overall length 57(0, breadth 48^, length of inner body 
37(jl, breadth 39(0. Range of dimensions — overall lengths 50-66(1, breadths 37- 5—52(0.. 

Description. The outer shell is basically ovoidal to polygonal ; but it is 
extremely thin and is deformed in variable fashion in the seven specimens examined. 
It bears folds or ridges which simulate a tabulation and is drawn out into a short 
apical horn with a blunt, slightly rounded tip. The inner body is spheroidal and 
typically broader than long. The periphragm is smooth ; the endophragm smooth 
or very minutely granular. The latter bears a moderately dense cover of tubercles ; 
these are conical and do not exceed i[x in height. There is some suggestion that the 
tubercles show a degree of alignment, but this could not be confirmed. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 211 

The archaeopyle is situated on the upper flanks of the epitract, in a position 
corresponding to the intercalary archaeopyle described by Evitt (1961c, text-fig. 7). 
The tabulation pattern was not sufficiently clear, however, to permit certainty as to 
whether the archaeopyle corresponded in position to an intercalary plate ; it is 
equally possible to visualize formation by loss of the equivalent of the anterior part 
only of a precingular plate. 

Remarks. Alberti (1961) recorded this form from the Lower Cretaceous (Upper 
Barremian) of Germany and commented that it probably constituted a new species. 
It occurs in the Lower Barremian horizons of the Speeton Clay (at 39 metres and 42- 5 
metres depth), but has not to date been encountered in the Upper Barremian. 

The generic allocation is made, following Alberti, on the basis of the tuberculate 
structure of the inner body ; however, a tabulation is typically absent in Dingo- 
dinium. It was not possible to determine the plate pattern in detail, but there 
proved to be some similarity to the pattern exhibited in Scriniodinium subgenus 
Endoscrinium Klement 1960c, to which the species is thus possibly referable. 

In the relative shapes of outer shell and inner body and in the ornamentation of the 
inner body ? Dingodinium albertii sp. nov. differs from all other described species. 

Genus PAREODINIA Deflandre 1947 : 4 

Type species. Pareodinia ceratophora Deflandre 1947. Middle Jurassic ; 
France. 

Pareodinia ceratophora Deflandre 

PI. 23, fig. 2 

1947. Pareodinia ceratophora Deflandre : 4, text-figs. 1-3. 
1958. Pareodinia aphelia (para) Cookson & Eisenack : 60, pi. 12, fig. 9. 

1958. Cryptomeriapollenites coralliensis Lantz (nom. nud.) : 927, pi. 5, figs. 55-56, pi. 6, fig. 7. 
1958. Incertae sedis, Lantz : 927, pi. 6, figs. 58-59. 
19606. Pareodinia ceratophora Deflandre ; Sarjeant, pi. 12, fig. 11. 
1961a. Pareodinia ceratophora Deflandre ; Sarjeant : 99, pi. 13, fig. 16. 
1 961. Pareodinia ceratophora Deflandre ; Alberti : 23, pi. 12, fig. 14. 
1961. Peridinea (?) Maliavkina, Samoilovitch et al., pi. 16, figs, i, ?2. 
1961. Pareodinia sp., Evitt, pi. 8, fig. 19. 

1962a. Pareodinia ceratophora Deflandre ; Sarjeant : 263, pi. 1, fig. 13. 
19626. Pareodinia certophora Deflandre ; Sarjeant : 483, pi. 69, fig. 8 ; text-fig. 5. 
1963. Pareodinia ceratophora Deflandre ; Baltes : 584, pi. 4, fig. 7 (mis-spelt P. cerathophora 
in text). 

Remarks. This species, first described from the Middle Jurassic, is known to occur 
also in the Upper Jurassic. Cookson & Eisenack (1958) embraced within their 
species Pareodinia aphelia, from the Upper Jurassic to Lower Cretaceous of Australia, 
what they recognized as two distinct morphological entities ; one of these (type 2) 
corresponds exactly with Pareodinia ceratophora. In the Speeton Clay, this species 
is represented by a handful of specimens in the Hauterivian and Barremian horizons ; 
in the absence of any other evidence of reworking these must be presumed to be 



212 MKSOZOIC AND CAINOZOIC DINOFL AGELL ATE CYSTS 

indigenous. P. ceratophora thus emerges as having a known range from Callovian to 
Barremian. The shape and dimensions of the Speeton specimens accord with the 
range quoted by Deflandre as typical (overall length 65-78^), the figured specimen, 
B.M.(N.H.) slide ¥.51724(4), having an overall length of 71^, with apical horn 
I3"5(x long, and a breadth of S7'5V- 

Genus SIRMIODINI UM Alberti 1961 : 22 

Type species. 5. grossi Alberti 1961. Lower Cretaceous (U. Hauterivian-U. 
Barremian) ; Germany. 

Sirmiodinium grossi Alberti 
PL 22, fig. 7 

1961. Sirmiodinium grossi Alberti : 22, pi. 7, figs. 5-7, pi. 12, fig. 5. 

Remarks. This species is represented in four studied horizons of the Speeton 
Clay, at 39-0, 42-5, 99-25 and 103-25 metres depth. (Middle Hauterivian to Lower 
Barremian.) The range of dimensions exhibited is similar to, but somewhat greater 
than, that quoted by Alberti (overall length 87-92^, breadth 8i-85[x) ; the figured 
specimen, B.M.(N.H.) slide ¥.51722(2), having the dimensions overall length 95^, 
breadth 8^\i, length of inner body 65^, breadth 63^.. 

Genus COMETODINIUM Deflandre & Courteville 1939 : 98 

Type species. C. obscurum Deflandre & Courteville 1939. U. Cretaceous ; 
France. 

Cometodinium sp. 

PI. 22, fig. 6 

Description. Shell spherical to spheroidal, minutely granular, densely covered 
by a mat of undulose hairlike spines. The spine-cover is lacking only in a narrow 
median belt corresponding to the cingulum ; this may be partly or wholly obscured 
from view, by the tangled spines. Archaeopyle not seen. 

Figured specimen. B.M.(N.H.) slide ¥.51723(2), Speeton Clay, Shell West 
Heslerton Borehole at 42-5 metres depth, West Heslerton, Yorks. Lower Cretaceous 
(Lower Barremian). 

Dimensions. Figured specimen : overall length 62jx, breadth 68jx, shell length 
37[x, breadth 44^, length of spines around i$\i.. Dimensions of other specimens 
closely similar. 

Remarks. This form has been encountered only at one horizon, in low numbers. 
It differs from Cometodinium obscurum in the lack of ridges edging the furrow ; the 
absence of any indication of a sulcus ; and the considerably shorter spines. It is 
perhaps more closely comparable to Baltisphaeridium whitei (Deflandre & Courteville 
1939), also from the Cretaceous of France ; this latter species lacks any trace of a 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 213 

cingulum, but then the cingulum is by no means easily seen in the Speeton specimens. 
It is therefore considered better not to propose a new name for these forms. 

Genus WETZELIELLA Eisenack 1938c : 186 
IWetzeliella neocomica Gocht 

1957. IWetzeliella neocomica Gocht ; 172, pi. 19, figs. 1-4, pi. 20, figs. 4, 6, 7 ; text-figs. 7, 8, 

15, 16. 
1 961. IWetzeliella neocomica Gocht ; Alberti : 11, pi. 4, figs. 17-19. 

Remarks. This species is represented by a number of poorly preserved specimens 
from two horizons (Hauterivian, 99-25 and 103-25 metres depth) of the Speeton 
Clay ; their dimensions fall within the range quoted by Gocht (overall length 72- 
H7[x, breadth 50-94(1) but only one specimen (B.M.(N.H.) slide ¥.51715(1)) is 
sufficiently well displayed to be measured in detail (overall length i03[x., breadth gojx). 
The attribution of this species to the genus Wetzeliella was made with hesitation by 
Gocht and must be considered doubtful, since archaeopyle formation is apical and 
not intercalary as in typical species of that genus. However, the English specimens 
are too poorly preserved to be used as bases for the erection of a new genus. 

It is probable that this species is related to Muderongia. Evitt (1961 : 397, pi. 8, 
figs. 1, 2) has figured as " Form G " a species from the Lower Cretaceous Dilkuna 
Formation of Pakistan which appears exactly intermediate between this latter genus 
and 1W. neocomica. 

1 Wetzeliella neocomica was originally recorded from the Middle Hauterivian of 
Germany (Gocht 1957). Alberti (1961) has recorded it from the Lower Hauterivian 
to Upper Barremian of Germany, from the Hauterivian of Poland and Bulgaria and 
from the Upper Cretaceous (Turonian and Coniacian) of Germany. The fact that it 
has not yet been recorded from the Aptian, Albian or Cenomanian suggests that the 
Upper Cretaceous specimens were reworked. 

CONCLUSIONS 

The known distribution of species of fossil dinoflagellate cysts in the five Speeton 
Clay horizons examined, is shown in the accompanying Table. A striking feature 
which emerges is the major change occurring in the Upper Barremian, when the 
incoming of seven species combines with the disappearance of seven others to change 
the whole character of the assemblage. The apparent change between the assemb- 
lages from 99-25 metres depth (basal Upper Hauterivian) and 42-5 metres depth 
(upper Lower Barremian) may be expected to fade out when intermediate assembla- 
ges are examined. 

The 41 species listed in the table do not constitute the full array of dinoflagellate 
cysts from these five horizons ; there remains a number of species present in low 
numbers only and hitherto represented by damaged or obscured specimens, not 
capable of full description. The Speeton assemblages as a whole are remarkably 
rich and varied : it is clear that a number of species having a relatively limited 
stratigraphic range will prove of considerable value as stratigraphic indices. 



2I 4 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Table 5 



Horizon in the Speeton 
Clay of Shell West 
Heslerton No. 1 bore- 
hole, West Heslerton, 
Yorks. 

Species 



CVS 

in p 

u 

CD 
«T3 



.a e 

CV~ 

d > 



gH 

N CX 
&£? 



-C c: 


X! c 


.c -^ 


ft.S 


CV2 


c 
m 1 rt 




13 CD 


•a s 


i_, re 
+-> rn 
it ^ 




en 4) 


8 S 

CD " 


CD J-< 

+-> re 


S *- 


6 Ji 


u-> £ 


9? 




N 3 


0^ 3 


• CX| 
2*P 



Gonyaulacysta cretacea 


X 


X 








G. palla 






X 






G. helicoidea 






X 


X 




G. axicerastes 








X 




G. orthoceras 












G. episoma 










X 


G. hadra 










X 


G. aichmetes 










X 


Heslertonia heslertonensis 


X 


X 


X 


X 


X 


Heliodinium patriciae 


X 


X 








Hystrichodinium ramoides 




X 








Cribroperidinium sepimentum 


X 


X 








Leptodininm alectrolophum 








X 




Pareodinia ceratophora 




X 


X 


X 


X 


Pseudoceratium (Eopseudoceratium) gochti 




X 


X 


X 




Gardodinium eisenacki 


X 


X 


X 






G. albertii 


X 


X 








Muderongia crucis 




X 








M. staurota 






X 






?W etzeliella neocomica 


X 


X 








Odontochitina operculata 










X 


PBroomea longicornuta 










X 


Doidyx anaphrissa 






X 






Apteodinium maculatum 






X 






Dingodinium albertii 






X 


X 




Netrelytron trinetron 








X 




Paranett -elytron strongylum 






X 


X 




Sirmiodinium grossi 


X 


X 


X 


X 




Cometodinium sp. 






X 






Fromea amphora 










X 


Systematophora complicata 




X 


X 


X 




S. schindewolfi 






X 






Hystrichosphaera ramosa v. ramosa 








X 


X 


H. ramosa mullibreva 


X 


X 


X 


X 


X 


Hystrichosphaeridium simplicispinum 




X 


X 


X 


X 


H. arborispinum 






X 


X 




Oligosphaeridium complex 




X 


X 


X 


X 


0. vasiformum 


X 


X 


X 






0. macrotitbulum 


X 


X 








PCordosphaeridium fasciatum 






X 






Callaiosphaeridium asymmetricum 


X 


X 


X 


X 


X 



Stratigraphical distribution of dinoflagellate cysts in the Speeton Clay of Shell West Heslerton 

No. 1 Bore. 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 215 

XI. FURTHER DINOFL AGELLATE CYSTS FROM THE LONDON CLAY 

By G. L. WILLIAMS & C. DOWNIE 

INTRODUCTION 

A number of species of dinoflagellate cysts from the London Clay have been 
discussed in earlier chapters. However, there remains a large residue of species also 
considered to be indigenous ; these are discussed in the ensuing pages. Further 
work on assemblages from the lower part of the London Clay of the Sheppey area 
and from the Thanet Sands (horizons considered to be Paleocene) is at present in 
progress at Sheffield by Mr. A. Husain. 

Genus ADNATOSPHAERIDIUM nov. 

Diagnosis. Chorate cysts bearing tubular or solid intratabular processes varying 
in number on a single plate. Processes united distally by interconnecting trabeculae. 
Archeopyle apical. 

Type species. Adnatosphaeridium vittatum sp. nov. 

Discussion. Evitt (1961c) suggested that, in a taxonomic subdivision of Canno- 
sphaeropsis into separate genera, three factors needed to be taken into consideration : 
the type of archaeopyle ; the structure of the processes ; and the nature of the 
interconnections between processes. All these points need consideration, but the 
information at present available permits a subdivision into only two genera, recog- 
nized by type of archaeopyle and the position of processes with regard to plates. 
It is acknowledged that species now placed within Adnatosphaeridium represent 
different morphological types and that further subdivision will be necessary. 
Adnatosphaeridium includes species formerly placed in Cannosphaeropsis, which on 
account of their intratabular processes, apical archaeopyle and spherical to ellip- 
soidal shape, must be placed in a separate taxonomic category. When an archaeo- 
pyle is present, species of Adnatosphaeridium can be readily distinguished from 
those of Cannosphaeropsis. 

Adnatosphaeridium vittatum sp. nov. 
PI. 24, figs. 3, 7 ; Text-fig. 56 

Derivation of name. Latin ; vittatus, decorated or bound with ribbons. 

Diagnosis. Ellipsoidal central body, with thin granular wall bearing processes 
of two types : slender to broadly taeniate, greatly expanded distally, and hollow 
open branched. Former type predominating. Adjacent processes often united 
distally. Reflected tabulation ?', 6", 5'", ip and 1"". Archaeopyle apical. 

Holotype. B.M.(N.H.) slide ¥.519176(1). London Clay ; Sheppey, Kent, 
sample Sh.3. 

Dimensions. Holotype : diameter of central body 37^, by 47[x, length of 
processes up to 20\l. Observed range : diameter of central body, width 37-66^, 



2l6 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



length 28 (when archaeopyle present) to 52(1; Length of processes up to 3i[x. 
Number of specimens measured, 4. 

Description. Adnatosphaeridium vittatum has strongly developed taeniate 
processes, often exceeding I0[x in width, which may be arranged in linear, soleate, or 
annular complexes. In outline, the complexes can be tubiform to flaring, distally 
having two orthogonal or recurved branches. The outer margin of the branches is 
frequently finely serrate. Branches of processes are interconnected with other 
processes on the same or adjacent plates. The interlinking of processes gives to 
them the appearance of natural arches. Some of the processes are simple and are 
oblate or bifid distally. Occasionally hollow branched open processes are present on 
the central body. Unconnected acuminate spines may arise from the processes. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. 

Remarks. A. vittatum is characterized by its taeniate processes of varying width, 
the presence of free and united processes and the occasional hollow branched proces- 
ses. The distal serrate terminations are unusual in this genus. 

Adnatosphaeridium multispinosum sp. nov. 
PL 24, fig. 5 ; Text-fig. 57 

Derivation of name. Latin ; multus, much, many : spinosns, thorny. 

Diagnosis. Ellipsoidal central body with thin granular endophragm. Archaeo- 
pyle apical, with zigzag margin. Periphragm forming numerous processes, slender, 
branched distally. Trabeculae possessing single unconnected acuminate spines. 



PRECINGULAR 
-PROCESS^ 




POSTCINdULAR 
PROCESS 



ANTAPICAL 
PROCESS 



Fig. 56. Adnatosphaeridium vittatum sp. nov. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 217 

Holotype. B.M.(N.H.) slide ¥.51975(1). London Clay ; Whitecliff, sample 
WC 16. 

Dimensions. Holotype : diameter of central body 44 by 59^. Length of 
processes up to 23^. Observed range : diameter of central body 44-71^. Length 
of processes up to 23^. Number of specimens measured, 3. 

Description. The processes of A. multispinosum are of approximately equal 
length in an individual and rarely exceed half the smaller diameter of the central body. 
They are erect or slightly curved, taeniate, branching from two thirds along their 
length to the distal extremity. The trabeculae often have short unconnected spines, 
sometimes arising from bulbous swellings ; the spines can be slender, up to 6jj. in 
length or short and conical. Occasional wider processes occur. The arrangement of 
the processes on the central body is variable ; they can lack any regularity or be in 
soleate or annular complexes. 

Occurrence. Eocene, London Clay ; Whitecliff. 

Remarks. A. multispinosum differs from A. filiferum (= Cannosphaeropsis 
filifera Cookson & Eisenack) in possessing more numerous, generally very slender 
processes which can branch from two thirds along their length. Cannosphaeropsis 
tutulosa Cookson & Eisenack (1960a), from the Upper Cretaceous of Australia, has 
fewer processes which divide distally and join with neighbouring branches to form a 
series of relatively wide deep loops apparently lacking spines. 

? Adnatosphaeridium patulutn sp. nov. 
PL 24, figs. 1, 2 ; Text-fig. 58 

Derivation of name. Latin ; patulus, spread out, broad. 

Diagnosis. Sub-spherical central body with fibrous wall up to i\i thick, composed 
of endocoel and pericoel. Processes intratabular open, flared, with fibrous walls ; 
one per plate. Adjacent processes united distally. Archaeopyle haplotabular. 

Holotype. B.M.(N.H.) slide ¥.51977(1). London Clay ; Enborne, sample E 11. 




Fig. 57. Adnatosphaeridium multispinosum sp. nov. Holotype. 
Archaeopyle shaded, sulcal notch on the left. 



zi8 



MESOZOIC AND CA1NOZOIC DINOFLAGELLATE CYSTS 



Dimensions. Holotype : diameter of central body 75 by 8o\i. Length of 
processes up to ^jy.. Observed range : diameter of central body 75-95[x. Length 
of processes up to 37^. Number of specimens measured, 3. 

Description. ?A. patulum has a quadrate archaeopyle resulting from the loss of 
a single plate. The archaeopyle is surrounded by six processes in the holotype ; 
these may be precingular but until more specimens are studied definite conclusions 
cannot be drawn. The processes are considerably broader distally than proximally 
and have undulose margins. Distal margins of adjacent processes are united. 
The fibres of the process walls are haphazard in orientation. The walls often appear 
perforate and this may in part be due to differential staining. The central body is 
medium brown, the processes tranparent, yellowish green. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne and Sheppey. 

Remarks. The processes readily distinguish ?A. patulum from other described 
species. Because of the uncertainty with regard to the type of archaeopyle and its 
shape, the species is tentatively placed in Adnatosphaeridium. 

OTHER SPECIES 

Other species occurring in the London Clay and here referred to the genus Adnato- 
sphaeridium are A . fdamentosum (Cookson & Eisenack 1958), A. aemulum (Deflandre 
1938), A. caidleryi (Deflandre 1938), A. fdiferum (Cookson & Eisenack 1958), all 
thought to be derived. 




Fig. 58. Adnatosphaeridium patulum sp. nov. Holotype. 
Archaeopyle (haplotabular) is shaded. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 219 

Genus MEMBRANILARNACIA Eisenack 1963 : 99 
Emended diagnosis. Chorate cysts spherical, oval or ellipsoidal, usually thick 
walled and surrounded by more or less concentric and generally thin walled envelo- 
ping membrane supported by processes or supports normal to central body. Proces- 
ses forked, flared or branched distally. Shafts cylindrical or columnar. Archaeo- 
pyle apical. 

Type species. Membranilamax leptoderma Cookson & Eisenack 1958. Lower 
Cretaceous ; Papua. 

Discussion. Some of the species originally referred to the genus Membranilamax 
O. Wetzel (1933) were transferred to Membranilamicia by Eisenack (19636). Eisen- 
ack (1959c) reviewed Membranilamax and showed that the generic description 
given by O. Wetzel was ambiguous, embodying three distinct groups. These are : 

1. Forms with a spherical to oval central body surrounded by a membrane 
restricted to the equatorial region (pterate cysts). The membrane is 
supported by processes arising from the central body and branching distally. 
A pylome (or archaeopyle) has not been observed. 

2. Hystrichospheres with a spherical to oval central body surrounded by a 
concentric outer membrane which is supported by processes arising from the 
central body. A pylome (archaeopyle) can be present. 

3. Hystrichospheres with a central body surrounded by a concentric outer 
membrane, supported by raised crests, which form polygonal fields on the 
central body. A pylome can be present. 

To the first group can be attributed the type species of Membranilamax (M. 
pterospermoides O. Wetzel). The genus should therefore be restricted to species 
referable to group 1, but since the structure of the holotype of M. pterospermoides 
cannot be clarified because the specimen is too deeply embedded in a flake of flint 
and cannot be examined at high magnification, the placing of other species within 
Membranilamax is not to be recommended. 

Eisenack (1963&) erected two new genera according with the second and third 
types. These are Membranilamacia (corresponding to Group 2), and Valensiella 
(corresponding to Group 3 and synonymous with Favilamax Sarjeant 1963c over 
which it has seniority). Following Eisenack's abandonment of the name Membrani- 
lamax, all residual species left in that genus were provisionally transferred to 
Membranilamacia by Downie & Sarjeant (1964). Specimens from the London Clay 
attributable to the genus Membranilamacia possess intratabular processes indicating 
a reflected tabulation of 1-4', 6", 0-4C, 5'", ip, 1"". The archaeopyle is apical with 
a zigzag margin. From the tabulation and possession of intratabular processes, 
restricted to one per plate, Membranilamacia must be included in the family Hystri- 
chosphaeridiaceae and cannot therefore be the type genus of the family Membrani- 
larnacidiaceae. 

Membranilamacia is distinguished from the genus Adnatosphaeridium by having 
an outer membrane instead of trabeculae, which distally unite the processes of the 
latter genus. It is possible however that intermediate forms exist. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Membranilarnacia reticulata sp. 

PI. 24, figs. 4-6 ; Text-fig. 59 



nov. 



Derivation of name. Latin, reticulatus, net-like, netted. 

Diagnosis. Ellipsoidal central body with intratabular processes, one per plate. 
Processes indicating a tabulation of 1-4', 6", 4c, 5'", 1"". Cingular processes some- 
times absent. Sulcal processes and posterior intercalary process present on some 
individuals. Processes cylindrical, solid, fibrous, united distally by a fine reticulate 
membrane totally or partially enclosing central body. Processes rarely exceeding 
20[x in length. 




Fig. 59. Membranilarnacia reticulata sp. nov. a, Lower (ventral) surface, seen through 
the upper. Only part of the distal network uniting the processes is shown, b, Upper 
(dorsal) surface of same specimen, c, Lower (antapical) surface, seen through the upper. 
d, Upper (apical) surface of same specimen. Archaeopyle shaded, sulcal notch lies 
between plates 1" and 6". 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 221 

Holotype. B.M.(N.H.) slide ¥.51959(2), London Clay ; Sheppey, Kent, sample 
Sh 1. 

Dimensions. Holotype : diameter of central body 42 by 43[x. Length of 
processes up to 26^. Observed range : diameter of central body 35-44^. Length 
of processes 7-24^. Number of specimens measured, 8. 

Description. The central body has a thin wall, smooth or slightly granular, 
comprising the endophragm. When an archaeopyle is present, the zigzag margin 
sharply delimits six rectangular plates, each bearing a process. The sulcal notch is 
usually clearly discernible. The process denoting the posterior intercalary plate is 
more commonly absent. 

The fibrous processes rarely exceed two thirds of the diameter of the central body 
in length. They are generally simple and few in number, this being governed by the 
number of plates present. The size of the process may be a reflection of its position 
on the central body, the postcingulars often being smaller than the precingular 
processes. The cingulum appears to be slightly helicoidal. 

The meshwork of the reticulate membrane is variable in size within an individual : 
it is finer nearer the process. The membrane is not unlike a closely woven net in 
structure, with numerous fine interconnecting orthogonal threads. The membrane 
may be restricted to distinct zones as in the figured specimen. There the processes 
of each series of plates are distally united and have few interconnecting links with 
processes of other plate series. This can be useful in orientation since it clarifies the 
position of the different plate series, and particularly the pre- and postcingulars. 

Two variants of M. reticulata are recognized based on the arrangement of the 
processes. These are : 

Var. a. Reflected tabulation as in specific diagnosis but with no cingular processes. 
Sulcal processes may be present. This is the commoner of the two variants. 

Var. b. Tabulation as in specific diagnosis with cingular processes present, there 
being four in number. 

Variability in M. reticulata also extends to the number of apical processes, some 
specimens having one, others having four. However since it is impossible to dis- 
tinguish them when the archaeopyle is developed, the two forms are treated together 
as parts of the same species. 

Occurrence. London Clay ; Whitechff, Enborne and Sheppey. 

Remarks. Comparison of M. reticulata with other described forms suggests close 
affinity with Membranilarnax sp. O. Wetzel (1936), from the Upper Eocene of Ger- 
many. Reissinger (1950) figured a similar form which he simply termed a " hystri- 
chosphere ", this also being from the Eocene of Germany. Unfortunately neither of 
these specimens have been preserved, and only Wetzel attempted a description, 
brief in the extreme, stating that the form was a spiny sphere within an outer shell ; 
a description too succinct to be useful. 

Eisenack (19546) figured a specimen which he compared with Membranilarnax 
sp., O. Wetzel (1936). Eisenack (1959c) however inferred that the outer membrane 



222 MKSOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

of M. sp. docs not form a concentric surrounding network but is restricted to an 
equatorial zone, unlike that in M. reticulata. From the illustrations, Reissinger's 
form looks identical to M. reticulata, which often shows a conspicuous absence of the 
outer membrane in the equatorial zone when cingular processes are absent. 



Genus NEMATOSPHAEROPSIS Deflandre & Cookson 1955 : 268 

Emended diagnosis. Globular to ellipsoidal chorate cysts. Periphragm forms 
gonal or sutural processes united proximally by sutural ridges or membranes. 
Adjacent processes distally united by trabeculae. Archaeopyle precingular. 

Type species. Nematosphaeropsis balcombiana Deflandre & Cookson, 1955. 
Miocene ; Australia. 

Discussion. The tabulation of Nematosphaeropsis is identical to that of Hystri- 
chosphaera rarnosa. 



Nematosphaeropsis balcombiana Deflandre & Cookson 

z 955- Nematosphaeropsis balcombiana Deflandre & Cookson : 268, pi. 8, fig. 5. 

Discussion. Two specimens from the London Clay are attributed to N . bal- 
combiana. They closely agree with the type material, the dimensions being : central 
body, length 38-40(1, breadth 28-33^ ; process length io-22[x. The specimens were 
found in sample Wh 6 from Whitecliff and En from Enborne. 

Genus CANNOSPHAEROPSIS O. Wetzel 1932 : 140 

Emended diagnosis. Ellipsoidal chorate cyst with precingular archaeopyle and 
bearing branching or furcate processes like those of Hystrichosphaera in both struc- 
ture and distribution, but without sutural ridges or septa connecting their bases as in 
that genus. Processes interconnected distally by trabeculae. Endophragm and 
periphragm in close contact between bases of processes. 

Type species. Cannosphaeropsis utinensis O. Wetzel 1932. U. Cretaceous ; 
Baltic. 

Discussion. Evitt (1963) has pointed out that many species included within 
Cannosphaeropsis (according to Deflandre's (1947) definition) significantly differ 
from the type species. It is therefore proposed to restrict Cannosphaeropsis to 
species possessing gonal and sutural processes allied with a precingular archaeopyle ; 
species with intratabular processes and apical archaeopyle, formerly attributable to 
Cannosphaeropsis, have been transferred to the genus Adnatosphaeridium. 

No attempt is made to reallocate species of Cannosphaeropsis where the species in 
question have not been examined. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 223 

Cannosphaeropsis reticulensis Pastiels 
PL 24, fig. 8 

1948. Cannosphaeropsis reticulensis Pastiels : 49, pi. 5, figs. 7-10. 
1961. Cannosphaeropsis reticulensis Pastiels ; Alberti : 36, pi. 9, fig. 15. 

Discussion. Specimens of C. reticulensis possessing a precingular archaeopyle 
with gonal and sutural processes, are present in the London Clay. The intercon- 
necting trabeculae appear to be solid, taeniate and not tubular. The simple acumi- 
nate spines arising from the trabeculae of the type material are uncommon in the 
London Clay forms. 

Dimensions. Range observed in London Clay : diameter of central body 
26-43^, length of processes 9-i8[a. Number of specimens measured, 5. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne and Sheppey. 
C. reticulensis is also known from the Eocene of Belgium (Pastiels 1948) and Germany 
(Alberti 1961). 

Genus CYCLONEPHELIUM Deflandre & Cookson 1955 : 285 

Emended diagnosis. Chorate cysts with central body flattened dorso-ventrally 
and apparently concavo-convex, outline circular to slightly oval. Apex and/or 
antapex with or without blunt prominence, antapex occasionally slightly indented. 
Ornamentation restricted to circumferential zone of varying width, consisting of (1) 
processes, of varying lengths and shapes, distinct or more or less confluent, (2) thin 
membrane supported at intervals by strong processes, or (3) densely arranged surface 
thickenings. Ornamentation sometimes more strongly developed in antapical 
region. Archaeopyle apical tetrabular. Wall layers not distinguished. 

Type species. Cyclonephelium compactum Deflandre & Cookson 1955. Lower to 
Upper Cretaceous ; Australia. 

Discussion. Tabulation cannot be determined in this genus beyond the fact that 
there are four apical and six precingular plates. This is apparent from an examina- 
tion of a detached operculum and the margin of the archaeopyle, which is zigzag. 

The shape of specimens of Cyclonephelium is variable and is probably partly 
dependent on subsequent compression in the enclosing sediment. Individuals of the 
species C. exuberans Deflandre & Cookson 1955, are often similar to Areoligera in 
having a convex dorsal surface and a depressed ventral surface. This is not, 
however, universal, since others appear to have an ellipsoidal outline, both dorsal and 
ventral surfaces being convex. 

Cyclonephelium divaricatum sp. nov. 

PL 25, fig. 1 ; Text-fig. 60 

Derivation of name. Latin ; divaricatus, spread apart. 

Diagnosis. Central body flat or slightly convex with circular outline bearing 
numerous ambital taeniate processes. Processes united distally in complex 



224 MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 

fashion, sometimes by trabeculae, sometimes by perforated membranes. Erect 
unconnected secae, acuminate or bifid distally, arising from outer margin of trabecu- 
lae or membranes. Length of processes rarely exceeding one-third the diameter of 
the central body. 

Holotype. B.M.(N.H.) slide ¥.51956(2). London Clay ; Whitecliff, sample 8. 

Dimensions. Holotype : diameter of central body 54 by ji[L. Observed range : 
diameter of central body 45-711X. Length of processes up to I5fx. Number of 
specimens measured, 5. 

Description. The central body has a finely reticulate surface and is formed from 
the extremely thin endophragm. The periphragm gives rise to the taeniate processes. 
The numerous processes are restricted to the ambitus of the central body save on the 
precingulars, where the processes surround the archaeopyle margin. The processes 
are short, with only a few distal interconnctions. They tend to exhibit a linear 
orientation and are often united proximally. The secae, arising from the distal 
margin of the trabeculae or membranes that unite the processes, often appear to be 
continuations of the processes distally, whilst at other times they arise at points 
distant from the processes. Occasional simple acuminate processes are present on 
the central body. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne, Sheppey and 
Studland. 

Remarks. C. divaricatum differs from other described species of Cyclonephelium 
in the nature of the processes distally and the point of origin of the trabeculae or 
interconnecting membrane. 




OPERCULUM 
/ 



Fig. 60. Cyclonephelium divaricatum sp. nov. Partial drawing of specimen 
showing operculum separating from the test. 



I94 8 - 
1955- 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Cyclonephelium exuberans Deflandre & Cookson 
Text-fig. 61 

Membranilarnax pterospermoid.es Pastiels : 46, pi. 5, figs. 11-14. 
Cyclonephelium exuberans Deflandre & Cookson : 281. 



225 



Discussion. C. exuberans has probably evolved from C. pastielsi, intermediate 
forms between the two being common. Specimens from the London Clay show the 
same variation in process distribution as C. pastielsi, some individuals lacking 
processes on plates 3" and 6", others having processes on all the precingular plates, 
although generally with fewer on 3" and 6" than on the others. The prominent 
sulcal notch lies to the right of the mid-ventral line. The surface of the central body 
is commonly granular. 

Dimensions. Range observed in London Clay : diameter of central body 
56-85^, length of processes up to 46^. Number of specimens measured, 4. 

Occurrence. Eocene, London Clay ; Whitecliff and Enborne ; Eocene 
(Ypresian) of Belgium (Pastiels 1948). 

Cyclonephelium ordinatum sp. nov. 
PI. 25, fig. 3 ; Text-fig. 62 

Derivation of name. Latin ; ordinatus, in row, orderly. 

Diagnosis. Thin walled central body with granular surface. Processes formed 
from periphragm and restricted to linear complexes regularly distributed on central 




PRECINGULAR 
PROCESS 



Fig. 61. Cyclonephelium exuberans (Pastiels). Partial drawing showing large precingular 
processes around the margin of the archaeopyle (broken line). 



->J0 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



body. Reflected tabulation deduced from linear complexes of 4', 6", 5'", ip, 1"". 
Processes slender, solid, taeniate, united half to two-thirds along their length by 
membranes or trabeculae. Processes distally unconnected and unequally bifurcate. 

Holotype. B.M.(N.H.) slide ¥.51977(2). London Clay ; Enborne, Borehole 
E ii, 61 ft. 

Dimensions. Holotype : diameter of central body 61 by 73^. Length of proces- 
ses up to 36^. Observed range : diameter of central body <\i-j^\l, length of processes 
up to 40[x. Number of specimens measured, 4. 

Description. This species is unusual in that it possesses processes restricted to 
the ambitus yet which are grouped into linear or sometimes arcuate complexes 
reflecting a dinoflagellate tabulation. The apical archaeopyle is nearly always 
developed and had a clear sulcal notch. The precingulars possess a variable number 
of processes, plates 1", 2", 4" and 5" having well-developed linear complexes, 3" 
having a complex of varying extent, whilst 6" can be devoid of processes. 

The processes are not unlike those of Areoligera medusettiformis (O. Wetzel). The 
interconnecting membrane sometimes extends to the base of the processes and, if so 
developed, is often fenestrate proximally. Distally the processes are bifurcate 
commonly with one fork longer than the other and recurved. Occasionally the 
processes are acuminate. Branching can occur distally to the interconnecting 
membrane or trabeculae. 

Occurrence. Eocene, London Clay ; Whitecliff and Enborne. 






B 

ARCHAEOPYLE 



Fig. 62. Cyclonephelium ordinatum sp. nov. Holotype. a, Tabulation of the upper 
(dorsal) surface, b. Tabulation of the lower (ventral) surface seen through the upper, 
c, Partial drawing to show the ziz-zag nature of the archaeopyle margin. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 227 

Remarks. C. ordinum differs from C. divaricum in the regular arrangement of the 
processes in linear complexes and the larger overall size. It is included within the 
genus Cyclonephelium on account of the absence of processes from the mid-dorsal and 
ventral surface apart from those on the margin of the archaeopyle. 

Cyclonephelium pastielsi Deflandre & Cookson 
PI. 25, fig. 2 

1948. Membranilamax cf. liradiscoides Pastiels : 47, pi. 5, fig. 15. 
1955. Cyclonephelium pastielsi Deflandre & Cookson : 285. 

Discussion. Specimens of C. pastielsi from the London Clay almost invariably 
possess an archaeopyle, apical in position and with a zigzag margin. The prominent 
sulcal notch lies to the right of the mid-ventral line. Only rarely is a complete 
individual, with the apex in place, encountered. The numerous, solid taeniate 
processes are complexly united along their length and distally. They are frequently 
arranged in linear complexes. Proximally the processes arise singly or in groups of 
twos or threes. Distally the interconnecting trabeculae may be perforate, up to 5 to 
6[x in width. Unconnected short, slender, acuminate or bifid spines often arise from 
the trabeculae. Occasional simple acuminate processes occur on the central body. 

Pastiels figured a specimen of C. pastielsi (as Membranilamax cf . liradiscoides, pi. 5, 
fig. 15) showing an absence of processes round the mid-ventral and mid-dorsal mar- 
gins of the archaeopyle. In the majority of the London Clay forms the processes are 
rather more numerous on the ambitus and also completely surround the archaeopyle 
margin. Those processes round the archaeopyle are more complex in structure than 
the ambital processes, and are aligned in rows parallel to the margin of the archeo- 
pyle. It is probable that each precingular and postcingular plate has processes to a 
greater or lesser degree. 

Specimens of C. pastielsi can have two antapical protuberances, one more strongly 
developed than the other. When these are present the outline of the central body 
is closely comparable to that of Areoligera. The size of the London Clay forms 
usually exceeds that of the type material. Transitional forms to C. exuberans are 
not uncommon. 

Dimensions. Observed range in London Clay : diameter of central body 
43-90^, length of processes 12-38^. Number of specimens measured, 25. 

Occurrence. Common at all horizons of the London Clay. The forms having 
the larger central bodies are commonest in WC.14, 26 and E. 11/88. C. pastielsi 
has also been recorded from the Ypresian of Belgium (Pastiels 1948). 

Genus AREOLIGERA Lejeune-Carpentier 1938 : 164 

Emended diagnosis. Chorate cysts with hemispheral central body, convex 
dorsal side and flat or depressed ventral side. Processes intratabular, on dorsal 
surface arranged in soleate or annular complexes, on ventral surface in linear or 



228 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

occasionally soleate complexes. Plate i"" possesses an annular complex. Cingu- 
lum indicated by reduced linear complexes Reflected tabulation of 4', 6", 2-4C, 
5'", ip, 1"". Archaeopyle apical tetratabular. Well developed sulcal notch on 
ventral surface and lying to right of mid-ventral line. Outline of central body 
circular with bilobed antapex. 

Type species. Areoligera senonensis Lejeune-Carpentier 1938ft. Upper Cretace- 
ous (Senonian) ; Belgium. 

Discussion. Evitt (1961, 1963) has given a full and concise review of the genus. 
The close relationship to certain species of Cyclonephelium has been noted in preced- 
ing pages. 

Areoligera coronata (O. Wetzel) 
PI- 25, fig- 7 

1933. Hystrichosphaera penicillata forma coronata O. Wetzel : 41, pi. 4, fig. 17. 
1938. Areoligera coronata (O. Wetzel) Lejeune-Carpentier : 168, text-fig. 6. 

Discussion. A. coronata in the Eocene exhibits considerable variation in the 
structure of the soleate complexes. Proximally these can be fenestrate or non- 
fenestrate membranes, with the processes arising from the distal margin of the mem- 
brane. Alternatively, the processes may arise directly from the central body and be 
united along their length by membranes. Distally the slender processes are erect 
and can be acuminate or bifid. The number of processes per complex is variable 
Not infrequently plates 2'" and 4'" have annular and not soleate complexes ; if this 
is the case, the processes nearest the transverse cingulum are usually shorter. In 
one individual the processes of adjacent complexes are united distally by trabeculae. 

Only plate 6" never has processes. The apical plates possess four process groups, 
the smallest of which is that on plate 1'. This is a single taeniate process branched 
distally. Plates 2' and 3' have tubular annular complexes, diversely branched dis- 
tally ; these give the impression of having developed from a simple tubular process. 
Plate 4' has a taeniate process which is branched distally and is intermediate in size 
between process 1' and processes 2' and 3'. 

Dimensions. Range observed in London Clay : diameter of central body, 
length 53-66{i, breadth 57-76(0. ; length of processes 10-38(1. Number of specimens 
measured, 5. 

Occurrence. Eocene, London Clay ; Whitecliff and Sheppey ; Upper Cretace- 
ous of Germany (O. Wetzel 1933). 

Areoligera cf. coronata (O. Wetzel) 
PI. 25, fig. 5 ; Text-fig. 63 

Description. Included here are three specimens which differ from A. coronata 
in having process complexes on all the plates, 6" having a soleate complex, whilst 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



229 



plates 1'" and 5'" bear multibranched linear or annular complexes. There are at 
least four cingular plates and some sulcal plates having linear complexes. The 
dorsal surface is convex, the ventral surface depressed. The processes on the ventral 
surface are closer to those of A . medusettiformis than those of A . coronata, and can be 
simple or branched distally or proximally. 

A. cf. coronata resembles Systematophora in having process complexes on both 
ventral and dorsal surfaces. In the shape of the central body, position of the sulcal 
notch and predominance of soleate complexes however, it more closely approximates 
to Areoligera with which genus it must be included. 

Dimensions. Observed range : diameter of central body 57-71^, length of proces- 
ses up to 2J\l. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. 

Areoligera cf. medusettiformis (O. Wetzel) 
PL 25, fig. 4 

Description. This has similar processes to A . medusettiformis and the same shape 
of central body. It differs, however, in the presence of process complexes on all the 
fields and not on the dorsal fields only. The precingular plates bear soleate complex- 
es, whilst plates 1'" and 5'" have annular complexes. The complexes are unusual in 
being formed partly from simple processes, especially is this so with those processes 
nearest to the mid- ventral line. There is a well developed right antapical protuber- 
ance which is almost in line with the sulcal notch. 

Dimensions. Observed range : diameter of central body, 50-67^, length of 
processes up to 3fx. Number of specimens measured, 2. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. 





Fig. 63. Areoligera cf. coronata (O. Wetzel). Left, upper (ventral) surface ; right, lower 
(dorsal) surface, viewed through upper. Archaeopyle shaded. GP, girdle processes ; 
PS, posterior sulcal processes. 



230 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Areoligera cf. senonensis Lejeune-Carpentier 
PL 25, fig. 6 ; Text-fig. 64 

Description. One beautifully preserved individual from the London Clay of 
Sheppey, whilst having the distinctive processes of A. senonensis, also possesses 
process complexes on the ventral surface. The excellent preservation enabled the 
tabulation of 6", 5'", ip, 1"" to be determined. The six precingulars bear soleate 
process complexes, four of the postcingulars, 1'", 2'", 4'" and 5'" bear annular 
complexes. The single antapical protuberance lies immediately beneath the sulcal 
notch. 

A single archaeopyle operculum possessing four annular complexes can also be 
attributed to A. cf. senonensis. This has an elongate plate 1', with plates 2' and 3' 
considerably larger than the other two plates. 




Fig. 64. Areoligera cf. senonensis Lejeune-Carpentier. a, Tabulation of upper (ventral) 
surface with processes omitted, b, Tabulation of lower (dorsal) surface seen through the 
upper, c, An isolated operculum showing its tabulation. 



MESOZOIC AND CAINOZOIC DINOFL AGELL ATE CYSTS 231 

Dimensions. Diameter of central body 70 by 85jjl. Length of processes up to 

28(X. 

Occurrence. Eocene, London Clay ; Sheppey, Kent. 

Remarks. A. cf. senonensis, like A. cf. medusettiformis and A cf. coronata is a 
form approaching the genus Systematophora. The London Clay forms attributed to 
Areoligera, differ from Systematophora only because of the presence of process com- 
plexes on the central surface, in particular on plate 6" which is usually barren of 
processes. 

Genus DEFLANDREA Eisenack 1938 : 187 

Emended diagnosis. Cavate cysts with periphragm forming elongate pentagonal 
(also often somewhat rounded to rhomboidal) outer shell. Lateral walls usually 
convex. One apical and two antapical horns, more or less reduced. Tabulation, 
when decipherable, peridinoid. Periphragm smooth or granular. Cingulum circular 
longitudinal furrow if observable restricted to hypotract. Inner capsule circular to 
ovoidal in outline ; endophragm of variable thickness. Archaeopyle intercalary. 

Type species. D. phosphoritica Eisenack 1938. Oligocene ; East Prussia. 

Discussion. The genus Deflandrea is represented by a large number of species, 
some of which clearly overlap. To avoid further confusion, many specimens figured 
are not given a specific name or detailed description since slight changes in outline of 
the pericoel are not considered worthy of specific differentation. 

Deflandrea phosphoritica subsp. phosphoritica Cookson & Eisenack 

PI. 26, figs. 2, 3, 6, 9 

19616. Deflandrea phosphoritica subsp. phosphoritica Cookson & Eisenack : 39. 

Discussion. This subspecies, common in the London Clay, often possesses a 
clearly marked indented circular cingulum and a sulcus restricted to the hypotract 
and widening posteriorly. The outline of the periphragm varies from being identical 
to the type material to closely approaching Deflandrea phosphoritica subsp. australis 
Cookson & Eisenack 1961, which has a more granular periphragm and a short solid 
cylindrical process at the distal extremity of the apical horn and frequently more 
pronounced antapical horns. 

A few specimens without a capsule were observed ; in one the interior was empty, 
in the others formless organic matter appeared to have formed from decay of the 
capsule. 

The archaeopyle of the London Clay specimens of D. phosphoritica subsp. phos- 
phoritica is always intercalary in the periphragm but appears to occupy a more apical 
position in the endophragm. The granules on the surface of the periphragm often 
delimit plate boundaries and also tend to show linear alignment, running from the 
apex towards the antapex. 



232 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Dimensions. Observed range in London Clay : outer shell, length no-i33[x, 
breadth 75-103(0. ; capsule, length 55-75(x, breadth 66-86jjl. Number of specimens 
measured, 13. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne, Sheppey and Stud- 
land. Also from the Palaeocene to the Oligocene in Europe and the Lower Tertiary 
of Australia. 



Deflandrea phosphoritica subsp. australis Cookson & Eisenack 

PL 26, fig. 4 

19616. Deflandrea phosphoritca subsp. australis Cookson & Eisenack, pi. 1, figs. 2, 3. 

Discussion. Only three specimens from the London Clay can be definitely 
attributed to D. phosphoritica subsp. australis, although intermediate forms to 
D. phosphoritica subsp. phosphoritica are common. 

Dimensions. Observed range in London Clay : outer shell, length 138-157^, 
breadth 72-104^, capsule, length 69-75^, breadth ^2-6-Syy.. 

Occurrence. Eocene, London Clay ; Enborne and Sheppey. Also occurs in the 
Lower Tertiary of Australia (Cookson & Eisenack 1961&). 

Deflandrea denticulata Alberti 

1948. Peridinium cf. galeatum (pars.) Pastiels : 50, pi. 5, figs. 17-20. 
1959. Deflandrea denticulata Alberti ; 102, text-fig. 1. 

Discussion. The London Clay specimens attributable to D. denticulata are 
generally smaller than the type material and are sufficiently well preserved to give 
details of tabulation, determinable from the small acuminate or blunt processes that 
occasionally delimit the plate boundaries. These indicate the presence of four 
apical, three anterior intercalary, five postcingular, and as yet unknown numbers of 
precingular and antapical plates. The archaeopyle is intercalary, resulting from the 
loss of plate 2a. The tabulation of D. denticulata is thus peridinoid. The small 
processes, often longer on the prominent apical and antapical horns, are not restricted 
to the plate boundaries. They have a tendency to be orientated in linear complexes 
running in an antero-posterior direction. The sutures of the indented sulcus are 
always denticulate. 

Dimensions. Range in London Clay : outer shell, length 72-126-5^, breadth 
43-74^ ; capsule, length 37-64^ ; breadth 38-61^, length of apical horn 20-391X. 
Number of specimens measured, 15. 

Occurrence. Eocene, London Clay ; Whitecliff, Enborne and Sheppey. Also 
recorded from the Palaeocene to the Lower Eocene in Germany (Alberti 1959ft), and 
from the Ypresian in Belgium (Pastiels 1948). 



MESOZOIC AND CAINOZOIC DINOFL AGELLATE CYSTS 'a 

Deflandrea oebisfeldensis Alberti 
PL 26, fig. 1 

1959ft. Deflandrea oebisfeldensis Alberti : 95. pi. 8, figs. 10-13. 

Discussion. Two specimens from the London Clay are positively identified as 
D. oebisfeldensis ; one of them does not possess a capsule. 

Occurrence. Eocene, London Clay ; Enborne and Sheppey. Recorded also 
from the Palaeocene to the Lower Eocene in Germany and from Stalingrad, Russia 
(Alberti 19596). 



Deflandrea wardenensis sp. nov. 
PL 26, fig. 5 

Derivation of name. From Warden Point, Sheppey, Kent. 

Diagnosis. Cavate cysts, sub-circular to ovoidal periphragm, one apical and 
two short antapical horns. Conical apical horn merging imperceptibly into lateral 
walls; two antapical horns more positively delimited and straight or slightly diverging 
Length of antapical horns approximately equal. Thin walled ovoidal capsule, 
closely appressed to periphragm except at horns. Surface of periphragm has short 
acuminate or blunt processes, not restricted to sutures of cingulum and sulcus. 
Archaeopyle common. 

Holotype. B.M.(N.LL) slide ¥.51980(1). London Clay ; Sheppey, Kent, 
sample 2. 

Dimensions. Holotype : periphragm, length $j\l, breadth 46^ ; capsule, 
length 36^, breadth 43^. Observed range : periphragm, length 46-64^, breadth 
43-50^, capsule, length 33-41^, breadth 40-46^. Number of specimens measured, 
6. 

Description. The epitract is longer than the hypotract. In outline the former 
is conical with convex lateral sides, the latter is rounded with the antapical horns 
being sharply delimited. All three horns can be acuminate but are more commonly 
blunt. The antapical horns are well separated. The equatorial and longitudinal 
furrows are both wide with the latter broadening posteriorly. Five postcingulars 
have been discerned ; the rest of the tabulation is too difficult to decipher. 

Occurrence. Eocene, London Clay ; Sheppey, Whitecliff and Enborne. 

Remarks. Species of Deflandrea having processes on the sutures of the cingulum, 
sulcus and plate boundaries are D. denticulata ; D. echinoidea Cookson & Eisenack 
1958 (Upper Cretaceous ; Australia) ; and D. spinulosa Alberti 1959 (Oligocene ; 
Germany). All these have distinctive outlines which readily distinguish them from 
D. wardenensis. 



234 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

Genus THALASSIPHORA Eisenack & Gocht i960 : 51 

Emended diagnosis. Pterate cysts with spherical to ellipsoidal central body, 
smooth or more commonly granular. Periphragm in form of helmet-shaped 
" lamellar wing " and in contact with endophragm only on dorsal surface of central 
body. Archaeopyle precingular. 

Type species. Bion pelagicum Eisenack 1938. Oligocene ; East Prussia. 

Discussion. Thalassiphora Eisenack & Gocht is now considered to be referable to 
the Dinophyceae (Downie, Evitt & Sarjeant 1963) on account of the frequently 
occurring archaeopyle. As Alberti (1961) noted, the structure of Thalassiphora 
resembles that of Pterospermopsis superficially but detailed examination shows that 
in the former, the periphragm is attached to the endophragm on one surface of the 
central body only, the dorsal surface. The periphragm extends considerably 
beyond the central body as a wing lamella, in shape resembling an inverted basin 
with the margin often turned over. The position of the archaeopyle is constantly 
dorsal anterior, the keel when present, is posterior. If an archaeopyle is present, it 
occurs in the periphragm and endophragm. Free opercula are often encountered in 
sample. 

In Pterospermopsis, the wing lamella is in contact with the central body along an 
" equatorial zone " only. Species of Pterospermopsis do not possess an archaeopyle. 

Thalassiphora pelagica (Eisenack) 
PI. 26, fig. 7 

1938. Bion pelagicum. Eisenack : 187. 

1954. Pterospermopsis pelagica (Eisenack) Eisenack : 71, pi. 12, figs. 17, 18. 

i960. Thalassiphora pelagica (Eisenack) Eisenack & Gocht : 513, text-figs. 1-3. 

1961. Pterospermopsis pelagica (Eisenack) ; Gerlach : 209, pi. 28, fig. 15. 

1963. Thalassiphora pelagica (Eisenack) ; Gerlach : 50, pi. 3, fig. 3. 

1963. Thalassiphora pelagica (Eisenack) ; Brosius : 50, pi. 3, fig. 3. 

Discussion. T. pelagica is characterized by the presence of a keel on the peri- 
phragm. In the London Clay, orientation of the specimens has been guided by the 
position of the archaeopyle, which forms by the loss of a single precingular plate. 
The archaeopyle is anterior in position, the keel always being posterior with respect 
to this. The face of the central body containing the archaeopyle is dorsal. The 
archaeopyle is present in the periphragm and endophragm and has a convex tri- 
angular outline. Specimens with the operculum lying within the central body have 
been observed. The ovoidal central body has a wall up to i-$\i thick. The thick 
periphragm is fibrous with a reticulate ornamentation ; it can be perforate. In 
size, the London Clay forms show close agreement with the type material. 

Dimensions. Range observed in London Clay ; overall diameter 170-220^ ; 
central body 85-107^ ; archaeopyle 30-42^ ; keel I3[x. Number of specimens 
measured, 6. 

Occurrence. Eocene, London Clay ; Sheppey, Kent, and from the Upper 
Eocene to Middle Miocene of Germany. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 235 

Thalassiphora delicata sp. nov. 
PL 26, fig. 8 

Derivation of name. Latin ; delicatus, tender, dainty. 

Diagnosis. A Thalassiphora with ellipsoidal central body possessing a smooth 
thin wall. Periphragm in form of wing lamella, delicate, often irregularly folded and 
turned over on its margin. No keel present. Periphragm can be perforate. An 
archaeopyle may be present. 

Holotype. B.M.(N.LL) slide V. 51756(3). London Clay; Enborne, sample E 11. 

Dimensions. Holotype : diameter of central body 34 by 43^, overall diameter 
74 by 75fA. Observed range : diameter of central body 34-57EA, overall diameter 
74-i20(x. Number of specimens measured, 4. 

Description. T. delicata exhibits considerable variation in width of the peri- 
phragm, this is partly due to unequal folding. Some of the folds on the periphragm 
suggest the presence of a cingulum ; this is however difficult to visualise since the 
periphragm does not completely surround the central body. Both the endophragm 
and periphragm are thin. 

Remarks. This is only the third species allocated to this genus. It differs from 
the other two in size, the extremely thin periphragm and endophragm, the commonly 
perforate periphragm and the absence of a keel. 

XII. acknowledgments 

The authors have received help from many specialists in varying degree and would 
like to express their thanks for the ready and full co-operation afforded them. In 
particular they would like to thank Prof. Georges Deflandre, for much help and for 
courtesy in entertaining two of the authors (R.J.D. and W.A.S.S.) and allowing 
them to examine holotypes at the Laboratoire de Micropaleontologie, Ecole Pratique 
des Hautes Etudes, Paris ; Prof. A. Eisenack and Herr Hans Gocht, for their courtesy 
in entertaining two of the authors (CD. and W.A.S.S.) and permitting study of 
holotypes in the collections of the Geologisches Institut, University of Tubingen ; 
Dr. W. R. Evitt, of Stanford University, California, for much assistance in the formu- 
lation of the concepts here expressed ; Dr. J. W. Neale, of the University of Hull, 
and Dr. P. Kaye, of Burmah Oil Co., for their advice on Speeton Clay stratigraphy ; 
Mr. D. Curry for his advice on London Clay stratigraphy ; Dr. G. Norris, of McMast- 
ter University, Hamilton, Ontario, for profitable discussions, particularly on Gony- 
aulacysta and allied forms ; Dr. K. Diebel, of the Institut fur Palaontologie, 
Humboldt University, Berlin, for courteously permitting the loan, for study, of 
Ehrenberg's holotypes ; and Professors W. D. Evans and L. R. Moore, of the 
Universities of Nottingham and Sheffield, for their help and encouragement. 

They would further like to acknowledge the courtesy of Shell Internationale 
Research Maatschappij J.V., the Hague, Netherlands, for permitting study of 
Speeton Clay specimens from the West Heslerton No. 1 Borehole and for permitting 



236 MESOZOIC AND CAINOZOIC DINOFLAGELL ATE CYSTS 

publication of the relevant parts of this paper ; Professor H. L. Hawkins for making 
the Enborne Borehole cores available, and Sir James Stubblefield of H.M. Geological 
Survey, for permitting study of chalk specimens from the Fetcham Mill Borehole, and 
for permitting publication of the relevant parts of the paper. 

Finally, the assistance of Mrs. P. E. Lunn, Miss Eileen Bruce and Miss Denise 
Hales in the preparation of the manuscript, and of Mr. J. Eyett in photography, is 
gratefully acknowledged. 

The work of two of the authors (R.J.D. and G.L.W.) was done under the tenure of 
D.S.I.R. research studentships. 



MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 237 

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240 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 

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259- 



243 



INDEX 

New taxonomic names and the page numbers of the principal references are printed in Bold 

type. An asterisk (*) indicates a figure. 



Acanthogonyaulax, 132 

acanthosphaera, 132 

paliuros, 132 

venusta, 132 
Achomosphaera, 46 

alcicornu, 50, 104; PI. 5, fig. 3 

grallaeforme, 104 

hirundo, 104 

hyperacantha, 52 

neptuni, 51, 52; PI. 3, fig. 7, PI. 9, fig. 11 

ramulifera, 49; PI. 2, fig. 3 

var. perforata, 50; PI. 5, figs. 1, 4 

sagena, 51; PI. 2, figs. 1, 2 

triangulata, 52 
Adnatosphaeridium, 215 

aemulum, 218 

caulleryi, 218 

filamentosum, 218 

filiferum, 218 

multispinosum, 216, 217*; PI. 24, fig. 5 

patulum, 217, 218*; PI. 24, figs. 1, 2 

vittatum, 215, 216*; PI. 24, figs. 3, 7 
Alberti, G., 210 
Apteodinium, 204 

granulatum, 204 

maculatum, 205*; PI. 22, fig. 1 
Areoligera, 173, 227, 228 

coronata, 228, 229*; PI. 25, figs. 5, 7 

ga/ea, 173 

lychnea, 173 

medusettiformis 229, 230; PI. 25, fig. 4 

senonensis, 228, 230*, 231; PI. 25, fig. 6 



gilsonii, 174 

horridum, 174 

huguonioti, 174 

intermedium, 174 

longofilum, 174 

malleoferum, 174 

mariannae, 174 

panniforme, 174 

pattei, 174 

paucifurcatum , 174 

pectini/orme , 174 

plicatum, 174 

polyceratum, 174 

polyozon, 174 

quaternarium, 174 

saturnium, 175 

seminudum, 175 

spiculatum, 175 

stimuliferum , 175 

sylheti, 175 

lelmaticum, 175 

tinglewoodense, 175 

varispinosum, 175 

whitei, 175 
Belodinium, 109, 148 

dysculum, 148 
Bicavate cysts, 16 

BOWERBANK, J. S., 19, 69 

Broomea, 207 

longicornuta, 207; PI. 21, fig. 1 

ramosa, 207 
Brosius, M., 31 



Baltisphaeridium, 157, 174 
armatum, 174 
asteroideum, 174 
claviculorum , 174 
clavispinulosum, 174 
densicomatum , 174 
denticulatum, 174 
difforme, 174 
downiei, 174 
echiniplax, 174 
fimbriatum, 174 



Callaiosphaeridium, 103 

asymmetricum, 104; PI. 8, figs. 9, 10, PI. 9, 
fig. 2 
Cannosphaeropsis, 222 

reticulensis , 223; PI. 24, fig. 9 

utinensis, 222 
Carpodinium, 109, 139, 140 

granulatum, 139 
Cavate cysts, 16 

Chalk, Lower; historical background 19, 20 
stratigraphy 19, 20 



-M4 



INDEX 



Chorate cysts, 15, 16 
Cleistosphaeridium, 157, 166 

ancoriferum, 167, 168; PI. 19, fig. 1 

ashdodense, 170 

danicum, 170 

disjunctum, 169, 170; PI. 11, fig. 9 

diversispinosum, 167; PI. 10, fig. 7 

cchinoides, 170 

ehrenbergi, 170 

flexuosum, 169; PI. 2, fig. 5 

heteracanthum, 168, 169; PI. 2, figs. 6, 7 

israelianum, 170 

/we, 170 

lumcctum, 170 

machaerophonim, 170 

mtiltifurcatum, 170 

oligacanthnm, 170 

pectiniforme , 170 

pilosum, 170 

polytrichum, 170 

spiralisetum, 170 

tiara, 170 

tvibuliferum, 170 
Cometodinium , 212 

obscurum, 212 

sp. 212, 213; PI. 22, fig. 6 
Cookson, I. C, 19, 73, 159 
Cordosphaeridium , 83 

canlharelhim, 91 

cracenospinosum, 87; PI. 3, fig. 4 

difficile, 91 

diktyoplokus, 91 
subsp. latum, 91 

divergens, 89; PI. 12, fig. 2 

eoinodes, 91 

erectum, 91 

exilimurum, 87, 88; PI. 11, fig. 2 

fasciatum, 90, 91 ; PI. 7, figs. 5, 6 

fibrospinosum, 86; PI. 5, fig. 5 

floripes, 91 

subsp. breviradialum, 91 

gracilis, 84, 85*, 86; PI. 3, fig. 8, PI. 11, 
figs. 4, 6, 7 

inodes, 83, 84*; PI. 3, fig. 9 

latispinosum, 88, 89; PI. 5, fig. 8 

microlriaina, 91 

multispinosum, 89, 90; PI. 3, fig. 6 
Cryplarchaeodinium, 108 
Clenidodinium, 108, 154 

ornatum, 154 

tenellum, 154 
Curry, D., 20 



Cyclonephelium, 223 

compactum, 223 

divaricatum, 223, 224*; PI. 25, fig. 1 

exuberans, 225* 

ordinatum, 225, 226*, 227; PI. 25, fig. 3 

pastielsi, 227; PI. 25, fig. 2 
Cymatiosphaera membranacea, 104 
Cysts of dinoflagellates, 10, 12 
Cyst openings, 13, 14 



Davey, R. J., 19, 20, 28-106, 157-175, 181 

Davidson, S. E., 9, io, 17 

Deane, H., 19, 28, 58 

Deflandre, G., 9, 17, 28, 30, 53, 73, 137, 

158, 159, 181 
Deflandrea, 231 

denticulata, 232 

oebisfeldensis , 233; PI. 26, fig. 1 

phosphor itica, 231 

subsp. australis, 232; PI. 26, fig. 4 
subsp. phosphoritica, 231, 232; PI. 26, 
figs. 2, 3, 6, 9 

wardenensis, 233; PI. 26, fig. 5 
Dichadogonyaulax, 153 

culmula, 153 

pannea, 153 

schizoblata, 153 
Diebel, K., 32 
Diesing, K. M., 107 
Dingodinium, 210 

albertii, 210, 211 ; PI. 21, fig. 3, PI. 23, fig. 1 

jurassicum, 210 
Diphyes, 95, 96 

colligerum, 96, 97; PI. 4, figs. 2, 3 

monstruosum, 97 
Doidyx, 205, 206 

anaphrissa, 206*, 207 ; PI. 22, fig. 8, PI. 23, 
fig. 6 
Downie, C, 9, 10-17, 20-27, I 57-i98, 

215-235 
Duosphaeridium, 97 

nudum, 97 



Eagar, S. H., 9, 20 

Ehrenberg, C. G., 9, 28, 29, 31, 158 

ElSENACK, A., 9, 53, I57, 219 

Eisenackia, 108, 152 
crassitabulata, 152 
Enborne Valley, Berks., 23 
Eodinia, 109 
Evitt, W. R., 9, 10, 17, 28, 53-55, 222 



INDEX 



245 



Exochosphaeridium, 157, 165 
palmatum, 166 

phragmites, 165, 166; PI. 2, figs. 8-10 
striolatum, 166 

Fetcham Mill, Surrey, 19 
Fromea, 208 

amphora, 208, 209; PI. 22, fig. 4, PI. 23, 
fig- 3 

Gardodinium, 209 

eisenacki, 209, 210; PI. 21, fig. 4 
Glyphanodinium, 109, 152 

facetum, 152 
Gocht, H., 9 
Gonyaulacysta, no, 111 

aceras, 131 

aculeata, 130 

aichmetes, 123*, 124; PI. 13, figs. 5, 6 

amabilis, 130 

ambigua, 130 

apionis, 130 

aptiana, 130, 140 

axicerastes, 114, 115*, 116; PI. 13, figs. 
11, 12 

cassidata, 125*, 126; PI. 14, figs. 3, 4 

cladophora, 130 

clathrata, 130 

cornigera, 131 

crassicornuta, 130 

cretacea, 130 

diaphanis, 130 

edwardsi, 130 

eisenacki, 131 

episoma, 118*, 119; PI. 13, figs. 9, 10 

eumorpha, 131 

fetchamensis, 128, 129*, 130; PI. 15, 
figs. 1, 2 

freakei, 131 

gongylos, in, 112*, 113; PI. 13, figs. 1, 2 

granulata, 131 

granuligera, 131 

hadra, 119, 120*, 121; PI. 14, fig. 1 

helicoidea, 116, 117*; PI. 13, figs. 7, 8, PI. 
15, figs. 8, 9 

hyalodermopsis, 131 

jurassica, 12*, in 

longicornis, 131 

mamillifera, 131 

margaritifera, 131 

microceras, 131 

millioudi, 131 

muderongensis, 131 



ttatmctfmr, 132 
nealei, 132 
nuciformis, 132 
obscura, 131 

orthoceras, 121, 122*, 123; PI. 14, figs. 5, 6 
pachy 'derma, 131 

palla, 113*, 114; PI. 13, figs. 3, 4 
perforans, 131 
porosa, 132 
scarburghensis, 131 
scotti, 131 
serrata, 131 
tenuiceras, 131 
transparens, 132 
wetzeli, 131 

whitei, 126, 127*, 128; PI. 14. fig. 2 
Gonyaulax, 107, 108 
polyedra, 12* 
spinifera, 107 



Hawkins, H. L., 20 
Heliodinium, 109, 142 

patriciae, 144; PI. 16, fig. 1 

voigti, 142, 143*, 144; PI. 16, fig. 2 
Heslertonia, 133 

heslertonensis , 133 
Homotryblium, 55, 100 

pallidum, 102*, 103; PI. 12, figs. 4, 6 

tenuispinosum, 101*, 102; PI. 4, fig. n, 
PI. 12, figs. 1, 5, 7 
Hughes, M., 20 
Hughes, N. F., 9, 19 
Hystrichodinium, 109, 140, 141 

compactum, 142 

furcatum, 142 

oligacanthum, 142 

pulchrum, 141; PI. 16, figs. 7, 8 

ramoides, 142 
Hystrichokolpoma, 176 

clavigera, 181 

eisenacki, 176, 177*, 178; PI. 17, figs. 1-3 
var. turgidum, 178, 179; PI. 17, fig. 5 

ferox, 181 

rigaudae, 180; PI. 17, fig. 4 

tridactylites, 181 

unispinum, 179, 180; PI. 17, figs. 6, 7 

xiphea, 104 
Hystrichosphaera, 29, 108, no 

buccina, 42*, 43; PI. 4, fig. 1 

cingulata, 38; PI. 1, fig. 9 

var. reticulata, 39; PI. i, fig. 10, PI. 2, 
fig- 4 



246 



INDEX 



cornuta, 43, 44*, 45; PI. 4, fig. 7 

var. laevimura, 44, 45; PI. 4, fig. 5 

crassimurata, 39, 40; PI. 1, fig. 11 

crassipellis, 40, 41; PI. 1, figs. 7, 8 

furcata, 29-32 

leptoderma, 104 

monilis, 45, 46; PI. 5, fig. 2 

perforata, 41; PI. 5, fig. 7 

ratnosa, 29-32 

var. gracillis, 34, 35; PI. 1, fig. 5, PL 5, 

fig. 6 
var. granomembranacea, 37, 38; PI. 4 

fig- 4 
var. granosa, 35; PI. 4, fig. 9 
var. membranacea, 37; PI. 4, figs. 8, 12 
var. multibrevis, 35, 36*, 37; PI. 1, 

fig. 4, fig. 6 
var. ramosa, 33*, 34; PI. 1, figs, i, 6; 

PL 3. fig- i 
var. reticulata, 38; PI. 1, figs. 2, 3 

tertiaria, 43 

sp. 46; PI. 9, fig. 9 
Hystrichosphaeridium, 55, 56 

aquitanicum, 70 

arborispinum, 61 ; PI. 9, figs. 5, 10 

arundum, 70 

bowerbanki, 69, 70; PI. 8, figs. 1, 4 

clavigerum, 70 

costatum, 62, 63; PI. io, fig. 4 

deanei, 58, 59; PI. 6, figs. 4, 8 

gliwicense, 70 

Ai//i, 70 

irregulare, 70 

latirictum, 66; 67; PI. 10, fig. 8 

mantelli, 66; PI. 6, fig. 6 

patulum, 60; PI. 10, fig. 5 

polyplasium, 70 

radiculatum, 65; PL 7, fig. 8, PL 9, 
fig. 6 

readei, 64, 65 ; PL 6, fig. 3 

recurvation, 67, 68 

salpingophorum, 61, 62, 63; PL io, fig. 6 

simplicispinum, 59, 60; PL 9, fig. 3 

sheppeyense, 68, 69; PL 11, fig. 3 

stellatum, 70 

tubiferum, 56, 57*, 58; PL 6, figs. 1, 2, PL 8, 
fig. 5, PL 10, fig. 2 
var. brevispinosum, 58; PL 10, 
fig. 10 
Hystrichosphaeropsis, 138, 139 

borussica, 139 

ovum, 139 

wetzeli, 139 



Isle of Wight, 22, 23 



Kaye, P., 18 
Kilenyi, T. I., 18 
Klement, K. W., 108, 159 
Kofoid, C. A., 107 

Lejeune-Carpentier, M., 30, 31, 73, 159 
Leptodinium , 108, 133, 134 

alectrolophum, 134*, 135; PL 15, figs. 3-6 

arcuatum, 135 

maculatum, 135 

membranigerum, 136 

mirabile, 136 

tenuicornutum, 136 
Lithodinia, 108 
Litosphaeridium, 55, 79, 80 

crassipes, 83 

flosculus, 83 

inversibuccinum, 82; PL 12, fig. 3 

siphoniphorum, 80*, 81*, 82; PL 7, figs. 
7.8 

truncigerum, 83 

LOHMANN, H., 28 

London Clay; dinoflagellate assemblages 
Table 1, 
historical background, 20-27 
stratigraphy, 20-27 

Macko, S., 9, 20 
Maier, D., 31 
Mantell, G. A., 19, 28, 66 
Meiourogonyaulax, 144 

bulloidea, 146 

caytonensis, 146 

cristulata, 146 

valensii, 145*, 146; PL 15, fig. 7 
Membranate cysts, 16 
Membranilarnacia, 219 

pterospermoides, 219 

reticulata, 220*-222; PL 24, figs. 4-6 
Microdinium, 108, 148, 149 

ornatum, 149*-i5i; PL 16, figs. 3, 6 

setosum, 150, 151; PL 16, figs. 9, 10 
Morphology of dinoflagellate cysts, 10-16 
Motile stage thecae, 10, 12 
Muderongia, 202 

crucis, 204 

mcwhaei, 202 

perforata, 204 

simplex, 204 



INDEX 



247 



staurota, 203*, 204; PI. 21, figs. 6-7; PI. 

23. fig- 4 
tetracantha, 204 
tomaszowensis, 204 



Neale, J. W., 9, 18, 73 
Nematosphaeropsis, 222 

balcombiana, 222 
Netrelytron, 199 

jurassicum, 201 

stegastum, 199 

trinetron, 199, 200*, 201; PI. 22, fig. 3 
Norris, G., 17 



Odontochitina, 208 

operculata, 208; PI. 21, fig. 2 
Oligosphaeridium, 55, 70, 71 

albertense, 77 

anthophovum, 77 

asterigerum, 77 

coelenteratum, 77 

complex, 71, 72*, 73, 74; PI. 7, figs. 1, 2, PI. 

10, fig. 3 
dictyophorum, 77 
dispare, 77 
irregulare, 77 

macrotubulum , 75; PI. 9, fig. 4 
paradoxum, 77 
perforatum, 77 

prolixispinosum, 76, 77; PI. 8, figs. 2, 3 
pulcherrimum, 75, 76; PI. 10, fig. 9, PI. 11, 

fig- 5 
reniforme , 77 

retieulatum, 74; PI. 7, fig. 10 
vasiformum, 11*, 74, 75; PI. 9, fig. 7, PI. 10, 

fig. 1 



Paranetrelytron, 201 

strongylum, 201, 202;* PI. 21, fig. 5, 
PI. 23, fig. 5 
Pareodinia, 211 

aphelia, 211 

ceratopkora, 211, 212; PI. 23, fig. 2 
Pastiels, A., 92, 158 
Perisseiasphaeridium, 55, 78 

eisenacki, 79 

pannosum, 78*, 79; PI. 3, fig. 5, PI. 11, 
fig. 8 
Pluriarvalium, 109, 154 

osmingtonense, 154, 155*, 156 



Polysphaeridium, 55, 91, 92 

asperum, 95 

deflandrei , 95 

elegantulum , 95 

fabium, 95 

fluctuans, 95 

follium, 95 

fucosum, 95 

laminaspinosum, 94, 95; PI. 8, fig. 8 

major, 95 

marsupium, 95 

pastielsi, 92, 93; PI. 4, fig. 10 

paulinae, 95 

perovatum, 95 

polypes, 95 

pumilum, 93, 94; PI. 7, figs. 3, 4 

rhabdophorum, 95 

simplex, 95 

subtile, 92; PI. 11, fig. 1 

tribrachiosum, 95 

zoharyi, 95 
Prolixosphaeridium, 157, 171 

deirense, 171*, 172; PI. 3, fig. 2 

granulosum, 172 

mixtispinosum, 173 

parvispinum, 173 

xanthiopyxides, 173 
Proximate cysts, 14 
Proximochorate cysts, 15 
Pritchard, A., 158 
Psaligonyaulax, 136, 

apaletum, 138 

deflandrei, 137*, 138; PI. 14, figs. 6, 7 

simplicia, 138 
Pterate cysts, 16 

Pterocavate cysts, 16 

Raphidodinium, 109, 136 

fucatum, 146 
Reade, Rev. J. B., 19, 28, 64 
Reinsch, P. F., 28 
Rhaetogonyaulax, 152, 153 

chaloneri, 153 

rhaetica, 153 
Rhynchodiniopsis, 109, 140 

aptiana, 140 
Rottnestia, 139 

Sarjeant, W. A. S., 9, 10-17, 18—20, 54, 73, 

107-175, 199-214 
Sheppey, Kent, 23, 27 
Sirmiodinium , 212 

grossi 212; PI. 22, fig. 7 



248 



INDEX 



Speeton Clay; dinoflagellate assemblages, 
Table 5, 
historical background 18, 19, 
stratigraphy 18, 19 
Staplin, F. L., 157 
Studland Bay, Dorset, 22 
Surculosphaeridium, 157, 160, 161 
cribrotubiferum, 161*, 162; PI. 9, fig. 6 
longifurcatum, 163*, 164*; PI. 8, figs. 7, 11 
vestitum, 162*, 163; PI. 9, fig. 8 
Systematophora, 209 
areolata, 209 
placacantha, 173 
schindewolfi, 209; PI. 22, fig. 5 

Tanyosphaeridium, 55, 98 

ellipticum, 100 

isocalamus, 100 

regulare, 99, 100; PI. 3, fig. 3 

variecalamum, 98,* 99; PI. 6, fig. 7 
Thalassiphora, 234 

delicata, 235; PI. 26, fig. 8 

pelagica, 234; PI. 26, fig. 7 
Trabeculate cysts, 15, 16 



Wetzeliella, 182 

subgen. Rhombodinium, 197 

glabra, 197, 198; PI. 20, figs. 9, 10 
subgen. Wetzeliella, 183 

articulata, 183, 184; PI. 18, figs. 1-4 

var. conopia, 184; PI. 18, fig. 5 
clathrata, 184, PL 18, fig. 6 
coleothrypta, 185*, 186; PI. 18, figs. 8, 9 
condylos, 193, 194; PI. 20, figs. 1, 2 
homomorpha, 190, 191 

var. quinquelata, 191, 192; PI. 18, 

fig- 7 
neocomica, 213 

ovalis, 192, 193; PI. 18, fig. 10 
reticulata, 187*, 188; PI. 19, figs. 3, 6 
similis, 194, 195; PI. 20, fig. 5 
solida, 195 
symmetrica, 196; PI. 20, fig. 6 

var. lobisca, 196; PI. 20, fig. 3 
tenuivirgula, 188*, 189; PI. 19, figs. 

2, 4 
var. crassoramosa, 189, 190*; PI. 
19, figs. 1, 5, 7 
varielongituda, 196, 197; PI. 20, figs. 4, 



Valensi, L., 9, 31, 73, 160 

Wall, D., 9 
Wanaea, 154 

spectabilis, 154 
West, R. G., 9 
West Heslerton, Yorks, 18 
Wetherell, E. W., 20 
Wetzel, O., 28, 30, 53, 158, 219 
Wetzel, W., 159, 160 



White, H. H., 19, 28, 29, 30, 53, 73, 126, 127 

White, M. C, 127 

Wilkinson, S. J., 19, 28 

Williams, G. L., 9, 20-27, 28-106, 157-198, 

215—235 
Wit, R. de, 159 



Xiphophoridium, 146, 147 

alatum, 147, 148; PI. 16, fig. 11 



PLATE i 

Fig. i. Hystrichosphaera ramosa (Ehrenberg) var. ramosa nov. Holotype. Slide xxv. 
Flint from Delitzsch. Humboldt-Universitat, Berlin. X400. 

Figs. 2, 3. Hystrichosphaera ramosa var. reticulata nov. Holotype. PF. 3038(1). 
X500. Fig. 3. Surface reticulation in focus. x 1250. 

Fig. 4. Hystrichosphaera ramosa var. multibrevis nov. Cenomanian (boring depth, 
670 feet). PF. 3040(2). X500. 

Fig. 5. Hystrichosphaera ramosa var. gracilis nov. Cenomanian (boring depth, 670 
feet). PF.304o(3). X500. 

Fig. 6. Hystrichosphaera ramosa var. ramosa nov. Cenomanian (boring depth, 730 
feet). P.F.3033(3). X500. 

Fig. 7. Hyst richosphaera crassipellis Deflandre & Cookson. PF. 3033(2). X500. 

Fig. 8. Hystrichosphaera crassipellis Deflandre & Cookson. Cenomanian (boring 
depth, 770 feet). Wall section to illustrate the unusual thickness. FM.77o(i). X975. 

Fig. 9. Hystrichosphaera cingulata (O. Wetzel). PF.3039(i). X500. 

Fig. 10. Hystrichosphaera cingulata var. reticulata nov. PF. 3039(2). X500. 

Fig. 11. Hystrichosphaera crassimurata sp. nov. Holotype, PF. 3040(1). X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 




■ **v 






PLATE 1 

. 1 



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i 

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10 



PLATE 2 

Figs, i, 2. Achomosphaera sagenasp. nov. Holotype. PF. 3041(1). Precingular arch- 
aeopyle shown. X500. Fig. 2. Surface reticulation in focus. X 1250. 

Fig. 3. Achomosphaera ramulifera (Deflandre). Cenomanian (boring depth, 840 feet). 
Precingular archaeopyle shown. FM. 840(1). X500. 

Fig. 4. Hystrichosphaera cingulata var. reticulata nov. Cenomanian (boring depth, 
730 feet). Lateral view, archaeopyle towards the north-west. PF. 3039(2). X5000. 

Fig. 5. Cleistosphaeridium flexuosum sp. nov. Holotype, PF.3045(i). X500 (phase 
contrast) . 

Fig. 6. Cleistosphaeridium heteracanthum (Deflandre & Cookson). PF-304i(2). 
Cenomanian (boring depth, 650 feet). Complete specimen showing form of processes. X500 
(phase contrast). 

Fig. 7. Cleistosphaeridium heteracanthum (Deflandre & Cookson). Cenomanian 
(boring depth, 840 feet). FM. 840/9. X500. 

Figs. 8-10. Exochosphaeridium phragmites gen. et sp. nov. 8, Cenomanian (boring 
depth, 810 feet). Apical process and cingular processes present. PF.3043(i). X500. 9, 10 
Holotype, PF.3035(3). Precingular archaeopyle to the north-west and apical process to the 
south-west, x 500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 2 



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PLATE 3 

Fig. i. Hystrichosphaera ramosa var. ramosa nov. Upper Oxfordian, Throstler Clay. 
V.5i7i4(i). X500. 

Fig. 2. Prolixosphaeridium deirense gen. et sp. nov. Holotype, ¥.51727(2). X500. 

Fig. 3. Tanyosphaeridium regulate sp. nov. Holotype, V. 51755(1). X500. 

Fig. 4. Cordosphaeridiosum cracenospinosum sp. nov. Holotype, V. 51748(1). X200. 

Fig. 5. Perisseiasphaeridium pannosum gen. et sp. nov. London Clay; Enborne boring 
(at 43-25 feet depth). E.n/71/9. X525. 

Fig. 6. Cordosphaeridium multispinosum sp. nov. Holotype, V.5i75i(i). X500. 

Fig. 7. Achomosphaera neptuni (Eisenack). V.5i7i6(i). X500. 

Fig. 8. Cordosphaeridium gracilis (Eisenack). V.5i746(i). X312. 

Fig. 9. Cordosphaeridium inodes (Klumpp). V.5i745(i). Apical view. X500. 



Bull B.M.{N.H.) Geol. Suppt. 3 



PLATE 3 





PLATE 4 

Fig. i. Hystrichosphaera buccina sp. nov. Holotype, ¥.51761(1). X400. 

Fig. 2. Diphyes colligerum (Defiandre & Cookson). ¥.51754(1). X500. 

Fig. 3. Diphyes colligerum (Deflandre & Cookson). London Clay; (85 feet above base 
of London Clay) Sheppey. Sh.3/i(i). Apical archaeopyle to the north-west. X500. 

Fig. 4. Hystrichosphaera ramosa var. granomembranacea nov. Holotype, ¥.51759(1). 
X500. 

Fig. 5. Hystrichosphaera cornuta var. laevimura nov. Holotype, ¥.51752(3). X500. 

Fig. 6. Hystrichosphaera ramosa var. multibreva nov. Holotype, ¥.51758(1). X500. 

Fig. 7. Hystrichosphaera cornuta Gerlach. ¥.51741(2). X550. 

Fig. 8. Hystrichosphaera ramosa var. membranacea (Rossignol). Membrane well 
developed on the apical pole. London Clay (173 feet above base of London Clay); Sheppey, 
Kent. Micropalaeont. Lab. Colin., University of Sheffield. X375. 

Fig. 9. Hystrichosphaera ramosa var. granosa nov. Holotype, ¥.51752(2). X500. 

Fig. 10. Poly sphae r idium pastielsi sp. nov. Holotype, ¥.51753(1). X425. 

Fig. 11. Homotryblium tenuispinosum gen. et sp. nov. An isolated plate bearing a 
single intratabular process. London Clay; Enborne boring (at 53 feet depth). E. 11/61/5(1). 
X750. 

Fig. 12. Hystrichosphaera ramosa var. membranacea (Rossignol). ¥.51747(2). 
X500. 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE 4 




PLATE 5 



Fig. i. Achomosphaera ramulifera var. perforata nov. London Clay ; Enborne 
(boring depth, 83-25 feet). Note precingular archaeopyle. WC. 3/6(1). X425. 

Fig. 2. Hystrichosphaera monilis sp. nov. Holotype, ¥.51763(1), X500. 

Fig. 3. Achomosphaera alcicornu (Eisenack). ¥.51765(1). X425. 

Fig. 4. Achomosphaera ramulifera var. perforata nov. Holotype, ¥.51764(1). X475. 

Fig. 5. Cordosphaeridium fibrospinosum sp. nov. Holotype, ¥.51747(1). X475. 

Fig. 6. Hystrichosphaera ratnosa var. gracilis nov. Holotype, ¥.51757(1). X350. 

Fig. 7. Hystrichosphaera perforata sp. nov. Holotype, ¥.51760(1). X550. 

Fig. 8. Cordosphaeridium latispinosum sp. nov. Holotype, ¥.51746(2). X640. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 5 












PLATE 6 

Fig. i. Hy st richosphaeridium tubife rum (Ehrenberg). Holotype. Slide XXV. Flint 
from Delitzsch. Humboldt-Universitat, Berlin. Apical view. X400. 

Fig. 2. Hyst richosphaeridium tubiferum (Ehrenberg). Holotype. Medial view. X400. 

Fig. 3. Hystrichosphaeridium readei sp. nov. Holotype, PF. 3030(2). X500. 

Fig. 4. Hystrichosphaeridium deanei sp. nov. Cenomanian (borehole depth, 690 feet). 
FM. 690/12(2). X400. 

Fig. 5. Cleistosphaeridium ancoriferum. Cenomanian (borehole depth, 810 feet). 
PF.3044(i). X500. 

Fig. 6. Hystrichosphaeridium mantelli sp. nov. Holotype, PF.3032(i). X500. 

Fig. 7. Tanyosphaeridium variecalamum gen. et sp. nov. Holotype, PF.3035(2). 
X500. 

Fig. 8. Hystrichosphaeridium deanei sp. nov. Holotype, PF.303o(i). X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 6 




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PLATE 7 

Fig. i. Oligosphaeridium complex (White). Neotype, lateral view. PF.3034(i) 
X500. 

Fig. 2. Oligosphaeridium complex (White). Cenomanian (borehole depth, 840 feet). 
Lateral view PF.3035(5). X 500. 

Fig. 3. Polysphaeridium pumilum sp. nov. Holotype, PF.3037(i). X975. 

Fig. 4. Polysphaeridium pumilum sp. nov. Cenomanian (borehole depth, 770 feet). 
FM.77o/7(i). X975- 

Fig. 5. ICordosphaeridium fasciatum sp. nov. Holotype, ¥.51719(1). X975. 

Fig. 6. ICordosphaeridium fasciatum sp. nov. Holotype. Nature of fibrous peri- 
phragm well shown. X975. 

Fig. 7. Litosphaeridium siphonipho rum (Cookson & Eisenack). Cenomanian (borehole 
depth 750 feet). Apical view showing 6-sided archaeopyle surrounded by 6 precingular pro- 
cesses. PF. 3037(3). X500. 

Fig. 8. Litosphaeridium siphon iphorum (Cookson & Eisenack). Cenomanian (bore hole 
depth, 770 feet). Antapical view. FM.77o/i(i). X500. 

Fig. 9. Hystrichosphaeridium radiculatum sp. nov. Cenomanian (borehole depth, 690 
feet). PF.303o(3). X500. 

Fig. 10. Oligosphaeridium reticulatum sp. nov. Holotype, lateral view, PF.3035(i). 
X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 

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PLATE 8 

Fig. i. Hystrichosphaeridium bowerbanki sp. nov. Cenomanian (borehole depth, 
750 feet). FM.75o/2(i). X500. 

Fig. 2. Oligosphaeridium prolixispinosum sp. nov. Cemonanian (borehole depth, 750 
feet). PF. 3037(2). X500. 

Fig. 3. Oligosphaeridium prolixispinum sp. nov. Holotype, PF.3036(i). X500. 

Fig. 4. Hystrichosphaeridium bowerbanki sp. nov. Holotype, PF.3033(i). X500. 

Fig. 5. Hystrichosphaeridium tubiferum (Ehrenberg). Cenomanian (borehole depth, 
690 feet). FM. 690/12(1). X500. 

Fig. 6. Hystrichosphaeridum radiculatum sp. nov. Holotype, PF.303i(i). X500. 

Fig. 7. Surculosphaeridium longifurcatum (Firtion). Cenomanian (borehole depth, 
730 feet). Antapical view. FM. 730/2(1). X500. 

Fig. 8. Polysphaeridium laminaspinosum sp. nov. Holotype, PF.3052(i). X975. 
(Phase contrast). 

Fig. 9. Callaiosphaeridium asymmetricum (Deflandre & Courteville) . Cenomanian 
(boring depth, 840 feet). Medial view in focus to show 6 large tubular cingular processes. 
FM. 840/6(1). X500. 

Fig. 10. Antapical view of same showing 5 postcingular processes. X500. 

Fig. 11. Surculosphaeridium longifurcatum (Firtion) PF.3042(i) Cenomanian (boring 
depth, 840 feet). Lateral view showing 3 series of processes — precingular, cingular and post- 
cingular. X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 






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PLATE 9 

Fig. i. Cleistosphaeridium ancoriferum (Cookson & Eisenack). Cenomanian (boring 
depth, 690 feet). Detached 6-sided apical region. FM. 690/4(1). X1250. (Phase contrast). 

Fig. 2. Callaiosphaeridium asymmetricum (Deflandre & Courteville) . Speeton Clay 
(at 10-325 metres depth). ¥.51716(2). X500. 

Fig. 3. Hystrichosphaeridium simplicispinum sp. nov. ¥.51729(2). X500. 

Fig. 4. Oligosphaeridium macrotubulum (Neale & Sarjeant). Holotype, ¥.51712(2). 
X400. 

Fig. 5. Hystrichosphaeridium arborispinum sp. nov. Speeton Clay (at 42 5 feet 
depth). ¥.51719(3). X500. 

Fig. 6. Surculosphaeridium cribrotubiferum (Sarjeant). Holotype, ¥.51735(1). x 500. 

Fig. 7. Oligosphaeridium vasiformum (Neale & Sarjeant). Holotype, ¥.51709(1). 
X400. 

Fig. 8. Surculosphaeridium vestitum (Deflandre). ¥.51736(1). X500. 

Fig. 9. Hystrichosphaera sp. ¥.51724(1). X500. 

Fig. 10. Hystrichosphaeridium arborispinum sp.nov. Holotype, ¥.51727(3). Lateral 
view. X500. 

Fig. 11. Achomosphaera neptuni (Eisenack). ¥.51717(1). Precingular archaeopyle to 
the north. X500. 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE £ 




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PLATE 10 

Fig. i. Oligosphaeridiutn vasijormum (Neale & Sarjeant). Holotype, V.5i709(3). 
Two precingular processes missing. x 400. 

Fig. 2. Hystrichosphaeridium tubiferum (Ehrenberg). London Clay ; (5 feet above 
base of London Clay) Sheppey. Sh. 1/2(1). X425. 

Fig. 3. Oligosphaeridiutn complex (White). London Clay ; (146 feet above base of 
London Clay) Whitecliff Bay. Apical archaeopyle (sutural notch to the west) surrounded by 
6 precingular processes. WC. 16/1(1). X425. 

Fig. 4. Hystrichosphaeridium costatum sp. nov. Holotype, V. 5 1708. X500. 

Fig. 5. Hystrichosphaeridium patulum sp. nov. Holotype, ¥.51739(1). X1250. 

Fig. 6. Hystrichosphaeridium salpingophorum (Defiandre). ¥.51734(1). X500. 

Fig. 7. Cleistosphaeridium diversispinosum gen. et sp. nov. Holotype, ¥.51750(1). 
X400. 

Fig. 8. Hystrichosphaeridium latirictum sp. nov. Holotype, ¥.51740(1). X975. 

Fig. 9. Oligosphaeridium pulcherrimum (Defiandre & Cookson). London Clay 
(78 feet above base of London Clay) ; Sheppey. Positions of the processes well shown, the 
absence of cingular processes being noticeable. Sh. 2/5(1). X875. 

Fig. 10. Hystrichosphaeridium tubiferumvar. brevispina nov. Holotype, ¥.51738(1). 
X500. 



Bull. B.M.(N.QJ Geol. Suppt. 3 

. ^¥ 

I; m 



PLATE 10 




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PLATE ii 

Fig. i. Polysphaeridium subtile gen. et sp. nov. Holotype, ¥.51752(1). X850. 

Fig. 2. Cordosphaeridium exilimurum sp. nov. London Clay (275 feet above base of 
London Clay) ; Whitecliff Bay. Archaeopyle well shown. ¥.51749(1). X425. 

Fig. 3. Hystrichosphaeridium sheppeyense sp. nov. Holotype, ¥.51741(1). X850. 

Fig. 4. Cordosphaeridium gracilis (Eisenack). London Clay (731 feet above base of 
London Clay) ; Sheppey. Detached apical plate. Sh. 5/1(1). X450. 

Fig. 5. Oligosphaeridium pulcherrimum (Deflandre & Cookson). ¥.51742(1). Oper- 
culum only slightly displaced and bearing 4 apical processes. 

Fig. 6. Cordosphaeridium gracilis (Eisenack). London Clay (173 feet above base of 
London Clay) ; Sheppey. Haplotabular archaeopyle well shown. ¥.51746(3). X400. 

Fig. 7. Cordosphaeridium gracilis (Eisenack). London Clay (173 feet above base of 
London Clay); Sheppey. Detached apical plate showing characteristic shape. Sh.5/i(2). 
X450. 

Fig. 8. Perisseiasphaeridium pannosum genet sp. nov. Holotype, ¥.51743(1). X500. 

Fig. 9. Cleistosphaeridium disjunction sp. nov. Holotype, ¥.51739(2). X400. 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE 11 













-- - 



* 7 





PLATE 12 

Fig. i. Homotryblium tenuispinosum sp. nov. London Clay ; Enborne (boring depth, 
53 feet). Complete specimen showing medial rupture. V. 51756(3). X500. 

Fig. 2. Cordosphaeridium divergens (Eisenack). London Clay ; Whitecliff, Isle of 
Wight. ¥.51750(1). X500. 

Fig. 3. } Litosphaeridium inversibuccinum sp. nov. Holotype, ¥.51744(1). Archaeo- 
pyle shown. X975. 

Fig. 4. Homotryblium pallidum sp. nov. London Clay; Enborne (boring depth, 53 feet). 
Epitractal operculum bearing apical and precingular processes. V. 51759(5). x 700. 

Fig. 5. Homotryblium tenuispinosum sp. nov. Holotype, V. 51756(1). X700. 

Fig. 6. Homotryblium pallidum sp. nov. Holotype, V. 51756(1). x8oo. 

Fig. 7. Homotryblium tenuispinosum sp. nov. London Clay (78 feet above base of 
London Clay) ; Sheppey. Enlargement of part of the epitract to show that it is composed of a 
number of polygonal plates, each bearing a single intratabular process. V. 51759(4). x 1200. 



Bull. B.M.{N.H.) Geo!. Suppt. 3 



PLATE 12 




/ . 



n 


s^^jULp 




• ffi 


tf^ 








4 




PLATE 13 

Gonyaulacysta gongylos sp. nov. 
Fig. 1. Ventral surface of holotype, V. 51708(1). X500. 
Fig. 2. Dorsal surface of holotype viewed by transparency. X500. 

Gonyaulacysta palla sp. nov. 
Fig. 3. Ventral surface of holotype, V. 51718(2). X500. 
Fig. 4. Dorsal surface of holotype. x 500. 

Gonyaulacysta aichmetes sp. nov. 
Fig. 5. Ventral surface of holotype, V. 51730(2). X 500. 
Fig. 6. Dorsal surface of holotype. X500. 

Gonyaulacysta helicoidea (Eisenack & Cookson) 
Fig. 7. Ventral surface of specimen, V. 51718(1). X500. 
Fig. 8. Dorsal surface of same, viewed by transparency. X500. 

Gonyaulacysta episoma sp. nov. 
Fig. 9. Ventral surface of holotype, V. 51730(1). 
Fig. 10. Dorsal surface of holotype, viewed by transparency. X500. 

Gonyaulacysta axicerastes sp. nov. 
Fig. 11. Ventral surface of holotype, V. 51727(1). X500. 
Fig. 12. Dorsal surface of holotype, viewed by transparency. X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 13 




PLATE 14 



Gonyaulacysta hadra sp. nov. 
Fig. 1. Dorsal surface of the holotype, V. 51731(1). The archaeopyle cover is within the 
shell. X500. 

Gonaulacysta whitei sp. nov. 
Fig. 2. Ventral surface of the holotype, PF. 3048(1). 

Gonyaulacysta cassidata (Eisenack & Cookson) 
Fig. 3. Ventral surface of specimen PF. 3047(1), viewed by transparency. X500. 
Fig. 4. Dorsal surface of same. x 500. 

Gonyaulacysta orthoceras (Eisenack) 
Fig. 5. Ventral surface of specimen, V. 51730(3). X500. 
Fig. 6. Dorsal surface of same, viewed by transparency. X500. 
Psaligonyaulax deflandrei gen. et. sp nov. 
Fig. 7. Ventral surface of the holotype, PF. 3049(1). X500. 
Fig. 8. Dorsal surface of same, viewed by transparency. x 500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 14 




PLATE 15 

Gonaylacysta fetchamense sp. nov. 
Fig. 1. Ventral surface of holotype, PF.3046(i). X500. 
Fig. 2. Dorsal surface of same, viewed by transparency. X500. 
Leptodinium alectrolophum sp. nov. 
Fig. 3. Ventral surface of paratype, V. 51725(1). X500. 
Fig. 4. Dorsal surface of same, viewed by transparency. X500. 
Fig. 5. Oblique view of dorsal surface of holotype, V. 51735(1). x 500. 
Fig. 6. Oblique view by transparency of the ventral surface of same. X500. 

Meiourogonyaulax valensii gen. et sp. nov. 
Fig. 7. Ventral surface of holotype. B.S.60 (Laboratoire de Micropaleontologie, Ecole 
Pratique des Hautes Etudes, Paris) . Photo, by Prof. G. Deflandre, reproduced by his permission. 
Xc.700. 

Gonyaulacysta helicoidea (Eisenack & Cookson) 
Fig. 8. Specimen, V.5i728(i), in oblique ventral view. X 500. 
Fig. 9. The same specimen, in oblique dorsal view, by transparency. X 500. 



Bull. B.M.{N.H.) Geo I. Suppt. 3 



PLATE 15 









a hi 














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PLATE 16 

Heliodinium patriciae Neale & Sarjeant 
Fig. i. The holotype, V. 51710(1), in lateral view. Photographed by phase contrast. X 500. 

Heliodinium voigti Alberti 
Fig. 2. Ventral surface of specimen, PF. 3035(4). X500. 

Microdinium cf. ornatum Cookson & Eisenack 
Fig. 3. A rather large specimen, oblique ventral view. X500. 
Fig. 4. The same specimen in oblique dorsal view, by transparency. X500. 
Fig. 5. Ventral surface of specimen, PF. 3050(1). X500. 
Fig. 6. Dorsal surface of same specimen, viewed by transparency. X 500. 

Hystrichodinium pulchrum Deflandre 
Fig. 7. Dorsal view of specimen V. 51737(1). X500. 
Fig. 8. Lateral view of specimen, V. 51737(2), showing archaeopyle. X500. 

Microdinium setosum sp. nov. 
Fig. 9. Ventral surface of holotype, PF.3046(2). X500. 
Fig. 10. Dorsal surface of same, viewed by transparency. X500. 

Xiphophoridium alatum (Cookson & Eisenack) 
Fig. 11. Antapical view of specimen. PF. 3051(1). X 500. 



Bull. B.M.{N.H.) Geol. Suppt. 3 

r. 



PLATE 16 



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PLATE 17 

Hystrichokolpoma eisenacki sp. nov. 
Fig. 1. Specimen showing the long antapical process, the slender equatorial processes and 
the deep sulcal notch. V. 51753(2). x66o. 
Fig. 2. Holotype, V. 51958(1). X 660. 

Fig. 3. Specimen with apical plates in position. V. 51752(4). x 400. 
Hystrichokoplorna rigaudae Deflandre & Cookson 
Fig. 4. Precingular, equatorial, and postcingular and antapical processes are clearly visible. 
V. 51757(2). X400. 

Hystrichokolpoma eisenacki var. turgidum nov. 
Fig. 5. Holotype. ^".51959(1). x 400. 

Hystrichokolpoma unispinum sp. nov. 
Fig. 6. Specimen with all processes buccinate. V. 51960(1). x66o. 

Fig. 7. Holotype. Apical view, sulcus marked by belt of small pores at top left. ¥.51961(1). 
X660. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 17 













1 



<,C- 



PLATE 18 

Wetzeliella (Wetzeliella) articulata Eisenack 
Fig. i. Specimen dorsal side uppermost showing archaeopyle, dorsal view. ¥.51955(2). 
X33o. 
Fig. 2. Specimen, ventral side uppermost. ¥.51961(1). X330. 

Fig. 3. Isolated periphragm operculum from archaeopyle of outer shell. Processes, except 
for central use, arranged in simulate complexes. ¥.51763(2). x 700. 

Fig. 4. Isolated endophragm operculum from archaeopyle of inner body. ¥.51763(2). 
X700. 

Wetzeliella (Wetzeliella) articulata var. conopia nov. 
Fig. 5. Specimen, dorsal side uppermost, with periphragm archaeopyle. Slightly displaced. 
¥.51962. X330. 

Wetzeliella (Wetzeliella) clathrata Eisenack 
Fig. 6. Narrow strips of minutely perforate membrane connect the distal ends of the pro- 
cesses. ¥.51958(2). X330. 

Wetzeliella (Wetzeliella) homomorpha var. quinquelata nov. 
Fig. 7. Specimen showing restriction of processes on the dorsal side to the simulate com- 
plexes. Periphragm operculum slightly displaced. ¥.51963(1). X330. 
Wetzeliella (Wetzeliella) coleothrypta sp. nov. 
Fig. 8. Holotype. ¥entral view. ¥.51753(3). X330. 
Fig. 9. Specimen with more numerous spines. ¥.51964(1). X330. 

Wetzeliella (Wetzeliella) ovalis Eisenack 
Fig. 10. Dorsal view of specimen with operculum slightly displaced. ¥.51965(1). X330. 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE 18 





^S&S 




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PLATE 19 

Wetzeliella (Wetzeliella) tenuavirgula var. crassoramosa nov. 

Fig. 1. Ventral view showing the simulate process complexes of plates 1', 11" and 7". V. 5 1966. 
X 1000. 

Fig. 5. Dorsal view showing simulate complex of intercalary plate 2a, with thick linking 
bars. V.51966. x 1000. 

Fig. 7. Ventral view, archaeopyle seen through ventral surface. Holotype. V.5ig54(2). 
X500. 

Wetzeliella (Wetzeliella) tenuivirgula sp. nov. 

Fig. 2. Dorsal view of holotype with archaeopyle V.5i964(2). X330. 

Fig. 4. Dorsal view showing periphragm archaeopyle formed by loss of plate 2a. Simulate 
complexes of plate ia, 3a, 4" and 5" surround it. V.5i752(5). xiooo. 
Wetzeliella (Wetzeliella) reticulata sp. nov. 

Fig. 3. Ventral view of holotype. V.5i752(6). X330. 

Fig. 6. Stimulate complex of plate 1 ' and adjacent plates, showing distal network. V. 51752 
(6). x 1000. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 19 




PLATE 20 

Wetzeliella (Wetzeliella) condylos sp. nov. 
Fig. 1. Ventral view of holo type. V.51967. X500. 
Fig. 2. Specimen with no apical horn. V. 51752(7). X500. 

Wetzeliella (Wetzeliella) symmetrica var. lobisca nov. 
Fig. 3. Ventral view. V.51970. X330. 

Wetzeliella (Wetzeliella) varielongituda sp. nov. 
Fig. 4. Holotype. Dorsal view, with operculum slightly displaced. V. 51973. X330. 
Fig. 8. Dorsal view, operculum inside inner body. V.51971. X330. 

Wetzeliella (Wetzeliella) similis Eisenack 
Fig. 5. Specimen with pyrite crystals concentrated in the horns. V. 51969. X330. 

Wetzeliella (Wetzeliella) symmetrica Weiler 
Fig. 6. Dorsal view. V.51974. X330. 

Wetzeliella (Wetzeliella) solida (Gocht) 
Fig. 7. Specimen with operculum lying within the central body. V. 51968. X330. 

Wetzeliella (Rhombodinium) glabra Cookson 
Fig. 9. Specimen with periphragm operculum in place. V.5i958(3). X 500. 
Fig. 10. Specimen with operculum missing. Periphragm has been colonized by fungi. 
V.51972. X500. 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE 20 







PLATE 21 

IBroomea longicornuta Alberti 
Fig. i. Specimen V.5i733(i). X500. 

Odontochitina operculata (O. Wetzel) 
Fig. 2. Specimen V.5i73o(4). xc.400. 

? Dingodinium albertii sp. nov. 
Fig. 3. Holotype, ¥.51719(2). X500. 

Gardodinium eisenacki Alberti 
Fig. 4. Specimen V.5 1726(1). X500. 

Paranetrelytron strongylum gen. et sp. nov. 
Fig. 5. Holotype, V.5i722(i). X500. 

Muderongia staurota sp. nov. 
Fig. 6. Holotype, ¥.51724(3). X650. 
Fig. 7. Paratype, ¥.51718(3). X650. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 21 














PLATE 22 

Apteodinium maculatum Eisenack & Cookson 
Fig. i. Specimen V.5 171 8(4). X650. 

Heslertonia heslertonense (Neale & Sarjeant) 
Fig. 2. Specimen V. 51724(2). X500. 

Netrelytron trinetron sp. nov. 
Fig. 3. Holotype, ¥.51729(1). X650. 

Fromea amphora Cookson & Eisenack 
Fig. 4. Specimen V.5 1 73 2(1). X500. 

Systematophora schindewolfi (Alberti) 
Fig. 5. Specimen V. 51721(1). X500. 

Cometodinium sp. 
Fig. 6. Specimen ¥.51723(2). X500. 

Sirmiodinium grossi Alberti 
Fig. 7. Specimen V. 51722(2). X500. 

Doidyx anaphrissa gen. et sp. nov. 
Fig. 8. Holotype, V.5i723(3). X750. 



Bull B.M.{N.H.) Geol. Suppt. 3 



PLATE 22 




*•■• f* y 



^ 



SS ft. 



PLATE 23 

? Dingodinium albertii sp. nov. 
Fig. 1. Holotype, V.5i7i9(2). highly magnified to show the tubercles. xc.1250. 

Pareodinia ceratophora Deflandre 
Fig. 2. Specimen V. 51724(4). X500. 

Fromea amphora Cookson & Eisenack 
Fig. 3. Specimen V. 51732(2). X500. 

Muderongia staurota sp. nov. 
Fig. 4. Specimen V.5 1724(5), lacking the apex as a result of archaeopyle formation. 

Paranetrelytron strongylum gen. et sp. nov. 
Fig. 5. Holotype, ^".51722(1), photographed by phase contrast at high magnification to 
show the separation of endophragm from periphragm. xc.1250. 

Doidyx anaphrissa gen. et sp. nov. 
Fig. 6. Specimen V. 51720(1), lacking the apex as a result of archaeopyle formation. x 500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 





V 






\ 



V 






g& 



\ 










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PLATE 24 

? Adnatosphaeridium patulum sp. nov. 
Fig. 1. Specimen with archaeopyle. V. 51975(2). X330. 
Fig. 2. Holotype Complete specimen. ¥.51977(1). X330. 

Adnatosphaeridium vittatum gen. et sp. nov. 
Fig. 3. Complete specimen. ¥.51753(4). X500. 
Fig. 7. Holotype with apical archaeopyle. ¥.51976(1). X500. 

Membranilarnacia reticulata sp. nov. 
Fig. 4. Holotype. ¥.51959(2). X500. 
Fig. 6. Specimen with apical archaeopyle. ¥.51754(2). X500. 

Adnatosphaeridium multispinosum sp. nov. 
Fig. 5. Specimen with apical archaeopyle. ¥.51975(1). x66o. 
Cannosphaeropsis reticulensis Pastiels 
Fig. 8. Complete specimen. ¥.51964(3). X500. 



Bull B.M.{N.H.) Geol. Suppt. 3 



PLATE 24 








PLATE 25 

Cyclonephelium divaricatum sp. nov. 
Fig. 1. Specimen with apical archaeopyle and processes on all plates, ¥.51956(2). X500. 

Cyclonephelium pastielsi Deflandre & Cookson 
Fig. 2. Specimen with operculum in place. ¥.51978(1). X500. 
Cyclonephelium ordinatum sp. nov. 
Fig. 3. Dorsal view of specimen with apical archaeopyle. ¥.51977(2). X330. 

Areoligera cf. medusettiformis (O. Wetzel) 
Fig. 4. Dorsal view of specimen with apical archaeopyle, note sulcal notch on the right of 
the mid-ventral line. ¥.51746(3). x66o. 

Areoligera cf. coronata (O. Wetzel) 
Fig. 5. Specimen showing the soleate process complexes on the ventral surface. ¥.51756(4). 
X660. 

Areoligera cf. senonensis Lejeune-Carpentier 
Fig. 6. Complete specimen. ¥.51757(3). x66o. 

Areoligera coronata (O. Wetzel) 
Fig. 7. Dorsal view. Processes arranged in soleate complexes, apical archaeopyle. ¥.51959 
(3)- X500. 



Bull. B.M.(N.H.) Geol. Suppt. 3 



PLATE 25 






wA' /^ 




PLATE 26 



Fig. 1. 

Fig. 2. 
X400. 

Fig. 3. 
X400. 

Fig. 6. 

Fig. 9. 

Fig. 4. 
Fig. 5. 
Fig. 7. 
Fig. 8. 



Deflandrea oebisfeldensis Alberti 
Specimen with endrophragm operculum slightly displaced. V. 51979. X400. 
Deflandrea phosphoritica subsp. phosphoritica Cookson & Eisenack 
Specimen with no inner body, periphragm operculum lying inside. V.5i753(5). 

Specimen showing girdle and slightly displaced periphragm operculum. V. 51955(3). 

Specimen with a "decomposed " inner body. ¥.51752(8). X400. 
Specimen with archaeopyle. V. 51747(3). X400. 

Deflandrea phosphoritica subsp. australis Cookson & Eisenack 
Complete specimen. ¥.51752(9). X400. 

Deflandrea wardensis sp. nov. 
Holotype with archaeopyle. ¥.51980(1). X400. 

Thalassiphora pelagica (Eisenack) 
An operculum is visible. V. 51757(4). X240. 

Thalassiphora delicata sp. nov. 
Holotype. ¥.51756(3). 



Bull. B.M.{N.H.) Geol. Suppt. 3 



PLATE 26 




Printed in England by Staples Printers Limited at their Kettering, Nortbanti, establishment 



APPENDIX II IS CONTAINED WITHIN THE 
1983 RE-ISSUE OP TTIE 7: ' Tli OR] 




APPENDIX TO "STUDIES ON 

MESOZOIC AND CAINOZOIC 

DINOFLAGELLATE CYSTS" 



R. J. DAVEY, C. DOWNIE, 

W. A. S. SARJEANT, AND 

G. L. WILLIAMS 



BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Appendix to Supplement No. 3 

LONDON: 1969 



APPENDIX TO "STUDIES ON MESOZOIC AND 
CAINOZOIC DINOFLAGELLATE CYSTS" 




BY 

ROGER JACK DAVEY, 
CHARLES DOWNIE, 

(University of Sheffield) 

WILLIAM ANTONY SWITHIN SARJEANT, 

(University of Nottingham) 

AND GRAHAM LEE WILLIAMS 

(Pan-American Petroleum Corp.) 



BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Appendix to Supplement 3 

LONDON : 1969 



THE BULLETIN OF THE BRITISH MUSEUM 

(natural history), instituted in 1949, is 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Appendix to Supplement No. 3 of the 
Geological (Palaeontological) series. The abbreviated 
titles of periodicals cited follow those of the World List 
of Scientific Periodicals. 



World List abbreviation 
Bull. Br. Mus. not. Hist. (Geol.) Suppl. 



Trustees of the British Museum (Natural History) 1969 



TRUSTEES OF THE 
BRITISH MUSEUM (NATURAL HISTORY) 

Issued 11 December, 1969 Price Sixteen Shillings 

i£o-8o) 



APPENDIX TO "STUDIES ON MESOZOIC AND 
CAINOZOIC DINOFLAGELLATE CYSTS" 

By ROGER JACK DAVEY, CHARLES DOWNIE, 

WILLIAM ANTONY SWITHIN SARJEANT, AND 

GRAHAM LEE WILLIAMS 

Manuscript accepted October 1968 



CONTENTS 

Synopsis ...... 

I. Introduction and Acknowledgements 
II. Generic reallocations (R. J. D. & G. L. W.) 
Genus Achomosphaera 
Genus Cymatiosphaera 
Genus ? Hystrichokolpoma 
Genus Hystrichosphaera . 
Genus Oligosphaeridium . 
Genus ? Litosphaeridium . 
Genus ? Cordosphaeridium 
Genus Perisseiasphaeridium 
Genus ?Polysphaeridium . 
Genus ?Diphyes 
Genus Tanyospkaeridium 

III. Taxonomic changes (W. A. S. S 

Genus Gonyaulacysta Deflandre emend 

Species of Gonyaulacysta 
Genus Leptodinium Klement emend 

Species of Leptodinium 
Genus Hystrichogonyaulax nov. 

Species of Hystrichogonyaulax 
Other Generic Reallocations 
Genus Dichadogonyaulax 
Genus ? Litosphaeridium . 
Genus Meiourogonyaulax 
Genus Polysphaeridium . 
Genus Psaligonyaulax 
Genus Rhaetogonyaulax . 

IV. Generic reallocations (R. J. D., C. D., W. A. S. 

Genus Areoligera . 
Genus Cleistosphaeridium 
Genus Exochosphaeridium 
Genus Prolixosphaeridium 
Genus Systematophora 
V. Generic reallocations (G. L. W. & C. D. 
Genus Adnatosphaeridium 
Genus Hystrichokolpoma . 
VI. Taxonomic revisions made by other authors 
VII. Errata and curatorial amendments 
VIII. References .... 



S. & G. L. W.) 



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4 APPENDIX TO "STUDIES ON MESOZOIC 

SYNOPSIS 

This Appendix comprises taxonomic revisions necessary to correct inadvertent errors in the 
Supplement and to take account of subsequent taxonomic studies. The diagnoses of two 
genera, Gonyaulacysta and Leptodinium, are emended ; a new genus, Hystrichogonyaulax, and 
two new species, Perisseiasphaeridium eisenackii and Polysphaeridinm belgicum, are proposed ; 
and revisions in the generic assignation of 114 other species are proposed. Typographical 
errors are corrected and curatorial amendments are incorporated. 

I. INTRODUCTION 

In a lengthy review (1967 ; 1030-3), Tappan & Loeblich Jnr. have noted that the 
new combinations resulting from generic reallocations proposed in our supplement 
in many instances failed to fulfil the requirements of Article 33, para. 4 of the 
" International Code of Botanical Nomenclature " (1961 edition, then applicable). 
This Appendix attempts to set these matters right. In sections II-V taxonomic 
reallocations are proposed ; in section VI, taxonomic reallocations by other authors 
are noted with comments; and in section VII, typographical and phraseological 
errors in the original work (some of them noted by the reviewers, others noted by 
the authors) are corrected and certain curatorial amendments to the numbering of 
specimens are listed. New species and new combinations which were validly 
published in the original work are not again listed here. 

The authors gratefully acknowledge helpful comments received from Dr. William 
R. Evitt (Stanford University, California) and Dr. Alfred R. Loeblich Jnr. (Chevron 
Research Company, La Habra, California). The work by W. A. S. Sarjeant was 
done whilst Visiting Professor at the University of Oklahoma, Norman, Oklahoma, 
U.S.A. : he would like to express personal thanks to Dr. Charles J. Mankin for his 
support and encouragement. 

II. GENERIC REALLOCATIONS (R.J.D. & G.L.W.) 

Achomosphaera alcicornu (Eisenack) Davey & Williams, comb, nov., =Hys- 

trichosphaeridium alcicornu Eisenack, 1954 ; 65-6, pi. 10 figs 1-2, text-fig. 5. 

Oligocene, East Prussia, U.S.S.R. 
Achomosphaera grallaef or me (Brosius) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium grallaeforme Brosius, 1963 ; 42 pi. 5 fig. 3, text-fig. 2 nos. 3 a-b. 

Oligocene, Germany. 
Achomosphaera hyperacantha (Deflandre & Cookson) Davey & Williams, comb. 

nov., =Hystrichosphaera hyperacantha Deflandre & Cookson, 1955 ; 264-5, 

pi. 6 fig. 7. Miocene, Australia. 
Achomosphaera hirundo (Eisenack) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium hirundo Eisenack, 1958 ; 404-5, pi. 24 fig. 12. Lower 

Cretaceous, Germany. 
Achomosphaera triangulata (Gerlach) Davey & Williams, comb, nov., =Balti- 

sphaeridium triangulatum Gerlach, 1961 ; 194-5, pi. 29 fig. 1. Miocene, 

Germany. 



AND CAINOZOIC DINOFLAGELLATE CYSTS " 5 

Cymatiosphaera membranacea (Philippot) Davey & Williams, comb, nov., 

= Hystrichosphaeridium membranaceum Philippot, 1949 ; 57-8, text-fig. 3. 

Upper Cretaceous, France. (Acritarch). 
}Hystrichokolpoma xiphea (Maier) Davey & Williams, comb, nov., =Galea 

xiphea Maier 1959 ; 309, pi. 30 fig. 5 (transferred to Hystrichosphaeridium by 

Sarjeant, 1964 ; 176). Oligocene, Germany. 
Hystrichosphaera leptoderma (Maier) Davey & Williams, comb, nov., = Hystri- 
chosphaeridium leptodermum Maier, 1959 ; 321-2, pi. 33 figs. 5-6. Oligocene, 

Germany. 
Oligosphaeridium albertense (Pocock) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium albertense Pocock, 1962 ; 82, pi. 15 figs. 226-7. Lower 

Cretaceous, Alberta, Canada. 
? Oligosphaeridium asterigerum (Gocht) Davey & Williams, comb, nov., 

= Hystrichosphaeridium asterigerum Gocht, 1959 ; 67-8, pis. 3 fig. 1, 7 figs. 1-3. 

Lower Cretaceous, Germany. 
? Oligosphaeridium coelenteratum (Tasch) Davey & Williams, comb, nov., 

= Hystrichosphaeridium coelenteratum Tasch in Tasch, McClure & Oftedahl, 

1964 ; 195, pi. 2 fig. 11. Lower Cretaceous, Kansas, U.S.A. 
Oligosphaeridium dictyophorum (Cookson and Eisenack) Davey & Williams, 

comb. nov.. = Hystrichosphaeridium dictyophorum Cookson & Eisenack, 1958 ; 

44, pi. 11 fig. 14. Upper Jurassic, Papua. 
^Oligosphaeridium dispare (Tasch) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium dispare Tasch in Tasch, McClure & Oftedahl, 1964 ; 195, pi. 2 

fig. 8. Lower Cretaceous, Kansas, U.S.A. 

^Oligosphaeridium irregular e (Pocock) Davey & Williams, comb, nov., = Hystri- 
chosphaeridium irregulare Pocock, 1962 ; 82-3, pi. 15 figs. 228-9, non Hystri- 
chosphaeridium irregular e (Merrill) Sarjeant, 1964. [The holotype of this 
latter species, originally described (as ?Geodia irregularis) from the Middle 
Cretaceous of Texas, U.S.A., is lost ; it is considered to be a junior synonym 
of Hystrichosphaeridium complex (White, 1842) Deflandre, 1946b, by Sarjeant, 
1966a ; 8]. Lower Cretaceous, Alberta, Canada. 

? Oligosphaeridium paradoxum (Brosius) Davey & Williams, comb, nov., 

= Hystrichosphaeridium paradoxum Brosius, 1963 ; 41-2, pi. 4 fig. 6, text-fig. 

2, nos. ia-c. Oligocene, Germany. 
Oligosphaeridium perforatum (Gocht) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium perforatum Gocht, 1959 ; 68-9, pis. 3 fig. 7 ; 7 figs. 13-16. 

Lower Cretaceous, Germany. 
}Litosphaeridium crassipes (Reade) Davey & Williams, comb, nov., —Xanthi- 

dium crassipes Reade, 1839 '< pi- 9 fig s - 2 ~5- (Transferred to Hystrichos- 

phaeridium by Lejeune-Carpentier, 1941 ; 79-80). Upper Cretaceous, England. 
}Litosphaeridium flosculus (Deflandre) Davey & Williams, comb, nov., =Hystri- 

chosphaeridium flosculus Deflandre, 1937 ; 75-6, pi. 15 figs. 5-6. Upper 

Cretaceous, France. 



6 APPENDIX TO "STUDIES ON MESOZOIC 

}Litosphaeridium truncigerum (Deflandre) Davey & Williams, comb, nov., 
= Hystrichosphaeridium truncigerum Deflandre, 1937 ; 71-2, pi. 13 figs. 6-7. 
Upper Cretaceous, France. 

ICordosphaeridium cantharellum (Brosius) Davey & Williams, comb, nov., 
=Hystrichosphaeridiitm cantharellum Brosius, 1963 ; 40-1, pi. 6 fig. 1, text-fig. 
2 nos. na-c. Oligocene, Germany. 

?Cordosphaeridium erectum (Manum & Cookson) Davey & Williams, comb, 
nov., = Hystrichosphaeridium erectum Manum & Cookson, 1964 ; 14, pi. 3 
figs. 5-6. Cretaceous, Arctic Canada. 

Perisseiasphaeridium eisenackii Davey & Williams, sp. nov., =Hystricho- 
sphaeridium anthophorum sensu Eisenack, 1958 ; 402, pi. 26 figs. 1-2 non 
Cookson & Eisenack, 1958. Holotype : the specimen figured by Eisenack, 
1958 ; pi. 26 fig. 1, and contained in his Slide Ob. Apt. no. 31. Dimensions of 
holotype : diameter of central body 55 [i, overall diameter iiojj.. Lower Creta- 
ceous (Upper Aptian), Germany. (Name originally proposed by Davey & 
Williams, 1966b ; 79 : invalid under Art. 37, since the holotype was not 
designated). 

?Polysphaeridium asperum (Maier) Davey & Williams, comb, nov., =Hystricho- 
sphaeridium asperum Maier, 1959 ; 319: pi. 33 fig. 2. Miocene, Germany. 

IPolysphaeridium deflandrei (Valensi) Davey & Williams, comb, nov., =Hystri- 
chosphaeridium deflandrei Valensi, 1947 ; 817-8, text-fig. 3. Middle Jurassic 
France. 

tPolysphaeridium fabium (Tasch) Davey & Williams, comb, nov., =Hystricho- 
sphaeridium fabium Tasch, in Tasch, McClure & Oftedahl, 1964 ; 195, pi. 2 
fig. 5. Lower Cretaceous, Kansas, U.S.A. 

}Polysphaeridium follium (Tasch) Davey & Williams, comb, nov., =Hystricho- 
sphaeridium follium Tasch, in Tasch, McClure & Oftedahl, 1964 ; 195, pi. 1 
fig. 8. Lower Cretaceous, Kansas, U.S.A. 

}Polysphaeridium fucosum (Valensi) Davey & Williams, comb, nov., =Micrhy- 
stridium fucosum Valensi, 1955a ; 40, text-fig. 2b (Transferred to Hystricho- 
sphaeridium by Downie and Sarjeant, 1963 ; 93). Cretaceous, France. 

?Polysphaeridium major (Lejeune-Carpentier) Davey & Williams, comb, nov., 
= Hystrichosphaeridium major Lejeune-Carpentier, 1940 ; 220-1, text-fig. 13. 
Upper Cretaceous, Belgium. 

}Polysphaeridium marsupiutn (Tasch) Davey & Williams, comb, nov., ^Hystri- 
chosphaeridium marsupium Tasch, in Tasch, McClure & Oftedahl, 1964 ; 193, 
pi. 3 fig. 16. Lower Cretaceous, Kansas, U.S.A. 

}Polysphaeridium paulinae (Valensi) Davey & Williams, comb, nov., =Micrhy- 
stridium paulinae Valensi, 1953 ; 48, pi. 12 fig. 6 (Transferred to Hystricho- 
sphaeridium by Downie and Sarjeant, 1963 ; 93). Middle Jurassic, France. 

? Polysphaeridium perovatum (Tasch) Davey & Williams, comb, nov., ^Hystri- 
chosphaeridium perovatum Tasch, in Tasch, McClure & Oftedahl, 1964 ; 194, 
pi. 3 fig. 13. Lower Cretaceous, Kansas, U.S.A. 



AND CAINOZOIC DINOFLAGELLATE CYSTS " 7 

?Polysphaeridium rhabdophorum (Valensi) Davey & Williams, comb, nov., 

= Hystrichosphaeridium rhabdophorum Valensi, 1955b ; 593-4, pi. 3 fig. 7. 

Cretaceous, France. 
}Polysphaeridium simplex (White) Davey & Williams, comb, nov., =Xanthidium 

tubiferum subsp. simplex White, 1842 ; 38-9, pi. 4 div. 3 fig. 10 (elevated to 

specific status, as Hystrichosphaeridium simplex, by Deflandre, 1946a ; card 

934). Upper Cretaceous, England. 
}Polysphaeridium tribrachiosum (Tasch) Davey & Williams, comb, nov., 

= Hystrichosphaeridium tribrachiosum Tasch in Tasch, McClure & Oftedahl, 

1964 ; 195, pi. 1 fig. 3. Lower Cretaceous, Kansas, U.S.A. 
IDiphyes monstruosum (Tasch) Davey & Williams, comb, nov., =Hystricho- 

sphaeridium monstruosum Tasch in Tasch, McClure & Oftedahl, 1964 ; 195, 

pi. 1 fig. 12. Lower Cretaceous, Kansas, U.S.A. 
Tanyosphaeridium ellipticum (Cookson) Davey & Williams, comb, nov., 

= Hystrichosphaeridium ellipticum Cookson, 1965 ; 87-8, pi. 11 figs. i-3a. 

Upper Eocene, Australia. 
Tanyosphaeridium isocalamus (Deflandre & Cookson) Davey & Williams, 

comb, nov., = Hystrichosphaeridium isocalamus Deflandre & Cookson, 1955 ; 

272, pi. 2 figs 7-8, text-figs 30-35. Lower Cretaceous, Australia. 



III. TAXONOMIC CHANGES PROPOSED BY W. A. S. SARJEANT 

In a recent publication, Wall (1967 ; 98) has discussed the difficulties encountered 
in distinguishing between the genera Gonyaulacysta and Leptodinium. Hitherto this 
had been done on the presence of a sixth precingular plate (numbered as plate 1'") 
in the former genus — a feature frequently difficult to discern, even in the type 
species, G. jurassica. Wall proceeded to formulate a revised diagnosis for the genus 
Leptodinium, emphasizing the absence of apical or antapical structures and the 
simplicity of the crests, which are typically low and lack spines or other outgrowths 
(1967 ; 104). This diagnosis did not take account of the revisions in these two 
genera proposed by Sarjeant (1966b ; 111, 113) ; and so revised diagnoses for the 
genera Gonyaulacysta and Leptodinium, embodying ideas drawn from both sources, 
are now given. Two species which fall outside the revised diagnoses of both genera 
are placed into a new genus, here proposed. 



Genus GONYAULACYSTA Deflandre ex Norris & Sarjeant 1965 
emend, Sarjeant, herein 

1964 Gonyaulacysta gen. nov. Deflandre : 5. [Type species not validly proposed : see 
I. C.B.N. Art. 33 para. 4]. 

1965 Gonyaulacysta Deflandre ; Norris and Sarjeant : 65. [Type species validly proposed]. 

1966 Gonyaulacysta Deflandre ; Loeblich & Loeblich : 33. 
1966b Gonyaulacysta Deflandre ; emend. Sarjeant : 111. 

1967 Gonyaulacysta Deflandre ; Wall : 98 (discussion only : no diagnosis given). 



8 APPENDIX TO "STUDIES ON MESOZOIC 

Emended diagnosis. Proximate dinoflagellate cysts, spherical, ovoidal, ellip- 
soidal or polyhedral, with an apical horn and the reflected tabulation 3-4', o-ia, 6", 
6c, 5-6"', 1 p, 0-1 p. v., 1"", o-xs. Cingulum strongly or weakly helicoid ; cingular 
plates well or poorly marked. Sulcus generally but not constantly extending on to 
the epitract ; undivided or subdivided into a variable number of small plates. 
Apical horn typically formed from the periphragm only, less frequently from both 
shell layers ; rarely, an apical or antapical pericoel is present (but not both), but the 
two layers are most often otherwise in continuous contact. Median and antapical 
horns lacking. Sutures marked by low ridges ; bearing crests of varied form 
(smooth, denticulate or spinous, perforate or imperforate) ; or marked by lines of 
spines of varied form. Height of spines or crests always less than J of shell width. 
A precingular single-plate archaeopyle, formed by loss of plate 3", is developed, the 
operculum typically becoming wholly detached : in some individual specimens, the 
archaeopyle may not be developed. Surface of periphragm smooth, granular, 
nodose, punctate or reticulate ; forms with a general spine cover are excluded. 

Type species. Gonyaulacysta jurassica (Defiandre) Norris & Sarjeant, 1965 
=Gonyaulax jurassica Defiandre, 1938 ; 168-70, pi. 6 figs. 2-5, text-figs. 1-2. 
Upper Jurassic (Oxfordian), France. 

Remarks. The diagnosis is emended to include the presence of an apical horn, 
formed by an outbulge of the periphragm or of both shell layers, as an essential 
characteristic. Species in which an apical prominence is developed merely from the 
junction of crests, such as Leptodinium freakei (Sarjeant) Sarjeant and Leptodinium 
millioudi (Sarjeant) Sarjeant, are excluded, as are species with a general spine cover 
or with especially long sutural spines (see discussion in Sarjeant, 1966b ; 111). 
Species having an apical or epitractal archaeopyle, species having a precingular 
archaeopyle formed by the loss of the equivalent of more than one plate, and species 
having a combination archaeopyle are excluded. The currently known range of the 
genus is Middle Jurassic — Miocene. 

Other species. 
Gonyaulacysta aculeata (Klement) Sarjeant, comb, nov., =Gonyaulax aculeata 

Klement, i960 ; 42-4, pi. 5 figs. 6-9, text-fig. 21. Upper Jurassic, Germany. 
Gonyaulacysta aichmetes Sarjeant, 1966b ; 123-4, pi- I 3 n g s - 5 _ 6, text-fig. 30. 

Lower Cretaceous, England. 
Gonyaulacysta ambigua (Defiandre) Sarjeant, comb. nov. =Gonyaulax ambigua 

Defiandre, 1939 ; 144, pi. 6 fig. 2. Upper Jurassic, France. 
(Note : The indirect citation of Deflandre's paper in Sarjeant 1968, does not 

conform to Art. 33 para. 3 and note 1 of the ' I. C.B.N.'. The new combination 

is, therefore, here reproposed.) 
Gonyaulacysta apionis (Cookson & Eisenack) Sarjeant, comb, nov., =Gonyaulax 

apionis Cookson & Eisenack, 1958 ; 36, pi. 3 fig. 7, text-figs. 3-4. Lower 

Cretaceous, Australia. 
Gonyaulacysta axicerastes Sarjeant, 1966b ; 114-6, pi. 13 figs. 11-12, text-fig. 

25. Lower Cretaceous, England. 



AND CAINOZOIC DINOFLAGELLATE CYSTS " g 

Gonyaulacysta cassidata (Eisenack & Cookson) Sarjeant, 1966b ; 125-6, pi. 14 

figs. 3-4, text-fig. 31 =Gonyaulax helicoidea subsp. cassidata Eisenack & 

Cookson, i960 ; 3, pi. 1, figs. 5-6. Lower Cretaceous, Australia. 
Gonyaulacysta cladophora (Deflandre) Sarjeant, comb, nov., =Gonyaulax 

cladophora Deflandre, 1938 ; 173-6, pi. 7 figs. 1-5, text-figs. 5-6. Upper 

Jurassic, France.* 
Gonyaulacysta confusa (Vozzhennikova) Sarjeant, comb, nov., =Gonyaulax 

confusus (sic) Vozzhennikova, 1967 : 80, pi. 17, figs. ia,b ; pi. 25, figs. 4-5, 

pi. 27, figs. 3-4. Upper Jurassic, U.S.S.R. 
Gonyaulacysta crassicornuta (Klement) Sarjeant, comb, nov., =Gonyaulax 

crassicormita Klement, i960 ; 38-9, pi. 5 figs. 1-3. Upper Jurassic, Germany. 
Gonyaulacysta cretacea (Neale & Sarjeant) Sarjeant, comb, nov., —Gonyaulax 

cretacea Neale & Sarjeant, 1962 ; 441-3, pi. 19 figs. 1-2, text-fig. 2. Lower 

Cretaceous, England. 
Gonyaulacysta crispa (W. Wetzel) Sarjeant, comb, nov., = Conyaulax crispa 

W. Wetzel 1966 ; 870, pi. 15, figs 4a-b. Middle Jurassic, Germany. 
Gonyaulacysta dangeardi Sarjeant, 1968 ; 226-7, pi. 1 fig. 21, pi. 3 figs. 8, 15, 

text-fig. 3. Upper Jurassic, France. 
Gonyaulacysta diaphanis (Cookson & Eisenack) Sarjeant, comb, nov., =Gony- 

aulax diaphanis Cookson & Eisenack, 1958 ; 36-7, pi. 3 figs. 13-14, text-figs. 

10-11. Lower Cretaceous, Australia. 
Gonyaulacysta dictyophora (Deflandre) Sarjeant, comb, nov., =Palaeoperidiniutn 

dictyophoruni Deflandre, 1938 ; 178-9, pi. 8 figs. 1-3. [Note : Sarjeant, 

1967 ; 249, formulated an emended diagnosis for this species and proposed its 

transfer to Gonyaulacysta. The generic transfer is, however, invalid in that the 

original place of publication cited was indirect (via the Downie & Sarjeant 

" Bibliography ") and not direct (I. C.B.N. Art 33 para. 1 and note 1). The 

emended diagnosis is considered applicable to this new combination.] Upper 

Jurassic, France. 
Gonyaulacysta eisenacki (Deflandre 1938 ; 171-3, pi. 6 figs. 7-10, text-figs. 

3-4) Sarjeant, 1968 ; 227, pi. 3 fig. 14. Upper Jurassic, France. 
Gonyaulacysta episoma Sarjeant, 1966b ; 118-19, pi. 13 figs. 9-10, text-fig. 27. 

Lower Cretaceous, England. 
Gonyaulacysta exilicristata Davey, 1968a ; 121, pi. 1, figs. 1-2, text-figs. 

9A-B. Upper Cretaceous, England. 
Gonyaulacysta fetchamensis Sarjeant 1966b ; 128-30, pi. 15 figs. 1-2, text-fig. 

33. Upper Cretaceous, England. 
Gonyaulacysta giuseppei (Morgenroth) Sarjeant, comb, nov., =Gonyaulax 

giuseppei Morgenroth, 1966 ; 5-6, pi. 2 figs. 3-6. Eocene, Germany. 
Gonyaulacysta gongylos Sarjeant, 1966b ; 111-13, pi. 13 figs. 1-2, text-fig. 23. 

Upper Jurassic, England. 
Gonyaulacysta gottisi Dupin 1968 ; 4, pi. 1 figs 7-12. Upper Jurassic, France. 
Gonyaulacysta granulata (Klement) Sarjeant, comb, nov., =Gonyatdax gramdata 

Klement, i960; 39-41, pi. 4 figs. 10-13, text-figs. 18-20. Upper Jurassic.Germany. 



io APPENDIX TO "STUDIES ON MESOZOIC 

Gonyaulacysta granuligera (Klement) Sarjeant, comb, nov., =Gonyaulax 

granuligera Klement, i960 ; 41-2, pi. 5 figs. 4-5. Upper Jurassic, Germany. 
Gonyaulacysta hadra Sarjeant, 1966b ; 119-21, pi. 14 fig. 1, text-fig. 28. Lower 

Cretaceous, England. 
Gonyaulacysta helicoidea (Eisenack & Cookson) Sarjeant, 1966b ; 1 16-17, pi. 13 

figs. 7-8, pi. 15 figs. 8-9, text-fig. 26, =Gonyaulax helicoidea Eisenack & Cookson, 

i960 ; 2-3, pi. 2, figs. 4-9. Lower Cretaceous, Australia. 
Gonyaulacysta hyaloderma (Deflandre, 1939 ; 144, pi. 6 figs 3-4) Sarjeant, 1967 ; 

252. Upper Jurassic, France. 
Gonyaulacysta hyalodermopsis (Cookson & Eisenack) Sarjeant, comb, nov., 

—Gonyaulax hyalodermopsis Cookson & Eisenack, 1958 ; 34, pi. 3 figs. 11-12, 

text-figs. 5-6. Lower Cretaceous, Australia. 
Gonyaulacysta longicornis (Downie) Sarjeant, comb, nov., =Gonyaulax longi- 

cornis Downie, 1957 ; 420, pi. 20 fig. 8, text-figs. 2a-b. Upper Jurassic, 

England. 
Gonyaulacysta kostromiensis (Vozzhennikova) Sarjeant, comb, nov., =Gonyaulax 

kostromiensis Vozzhennikova, 1967, 85-6, pi. 26, figs. 1-6, pi. 27, figs. 1-2. 

Lower Cretaceous, U.S.S.R. 
? Gonyaulacysta mamillifera (Deflandre) Sarjeant, comb, nov., =Gonyaulax 

mamillifera Deflandre, 1939 ; 143, pi. 6 fig. 1. Upper Jurassic, France. 
Gonyaulacysta microceras (Eisenack) Clarke & Verdier, 1967 ; 31, =Gonyaulax 

microceras Eisenack, 1958 ; 391, pi. 21 figs. 12-13. Lower Cretaceous, Germany. 
Gonyaulacysta monacantha (Deflandre, 1935 ; 228, pi. 6 fig. 1) Sarjeant, 1967 ; 

252. Upper Cretaceous, France. 
? Gonyaulacysta nannotrix (Deflandre) Sarjeant, comb, nov., =Gonyaulax 

nannotrix Deflandre, 1939 ; 143, pi. 6 fig. 7. Upper Jurassic, France. 
Gonyaulacysta nuciformis (Deflandre, 1938 ; 180, pi. 8 figs. 4-6, emend. 

Sarjeant, 1962b ; 482, pi. 6 fig. 6, text-fig. 4) Sarjeant, 1968 ; 227, pi. 3 fig. 4. 

Upper Jurassic, France. (Originally placed by Deflandre in the genus Palae- 

operidinium : later transferred to Gonyaulax by Sarjeant, 1962b). 
Gonyaulacysta obscura (Lejeune-Carpentier) Sarjeant, comb, nov., =Gonyaulax 

obscura Lejeune-Carpentier, 1946 ; 191-3, text-figs. 3-5. Upper Cretaceous, 

Belgium. 
Gonyaulacysta pachyderma (Deflandre) Sarjeant, comb, nov., =Gonyaulax 

pachyderma Deflandre, 1938 ; 176-8, pi. 7 figs. 6-10, text-figs. 7-10. Upper 

Jurassic, France. 
Gonyaulacysta palla Sarjeant, 1966b ; 113-4, pi. 13 figs. 3-4, text-fig. 24. Lower 

Cretaceous, England. 
Gonyaulacysta parorthoceras Davey, 1968b ; 1 { = G. orthoceras Sarjeant, 1966b ; 

121-3, pi. 14 figs. 5-6, text-fig. 29, —Gonyaulax orthoceras Eisenack, 1958, pi. 21 

figs. 3-11, pi. 24 fig. 1, text-figs. 2-3, pars). Lower Cretaceous, England. 
Gonyaulacysta perforans (Cookson and Eisenack) Sarjeant, comb, nov., =Gony- 

aulax perforans Cookson & Eisenack, 1958 ; 30-32, pi. 2 figs. 1-4, 7, 8, text-figs. 

8-9. Upper Jurassic, Papua. 



AND CAINOZOIC DINOFLAGELLATE CYSTS " n 

Gonyaulacysta pyra (Drugg) Sarjeant, comb, nov., =Gonyaulax pyra Drugg, 

1967 ; 14, pi. 1 fig. 17, pi. 9 figs. 6a-b. Upper Cretaceous-Paleocene, California, 

U.S.A. 
Gonyaulacysta sarjeanti (Vozzhennikova) Sarjeant, comb, nov., =Gonyaulax 

sarjeanti Vozzhennikova, 1967 ; 87-8, pi. 31, figs. 1-3. Upper Jurassic, 

U.S.S.R. 
Gonyaulacysta scarburghensis Sarjeant, 1964 ; 472-3 (=Gonyaulax areolata 

Sarjeant, 1961a ; 95-7, pi. 13 fig. 13, text-fig. 5, nom. nud.). Upper Jurassic, 

England. 
Gonyaulacysta scotti (Cookson & Eisenack) Sarjeant, comb, nov., =Gonyaulax 

scotti Cookson & Eisenack, 1958 ; 30, pi. 2 figs. 5-6. Upper Jurassic, 

Australia. 
Gonyaulacysta serrata (Cookson & Eisenack) Sarjeant, comb, nov., =Gonyaulax 

serrata Cookson & Eisenack, 1958 ; 34, pi. 3 fig. 2, text-figs. 12-14. Upper 

Jurassic-Lower Cretaceous, Papua. 
? Gonyaulacysta tenuiceras (Eisenack) Sarjeant, comb, nov., =Gonyaulax 

tenuiceras Eisenack, 1958 ; 389-91, pi. 21 figs. 14-15, pi. 22 figs. 1-3, pi. 24 

fig. 2, text-figs. 4-5. Lower Cretaceous, Germany. 
Gonyaulacysta tenuicornuta (Cookson & Eisenack) Sarjeant, comb, nov., 

= ? Leptodinium tenuicornutum Cookson & Eisenack, 1962 ; 478, pi. 3 figs. 

12-13, text-fig. ia, b. PLower Cretaceous, Australia. 
Gonyaulacysta tenuitabulata (Gerlach) Sarjeant, comb, nov., =Gonyaulax 

tenuitabulata Gerlach, 1961 ; 159-61, pi. 25 figs. 10-11, text-figs. 1-3. Oligo- 

cene-Miocene, Germany. 
"i Gonyaulacysta transparens (Sarjeant) Sarjeant, comb, nov., =Gonyaulax 

transparent Sarjeant, 1959 ; 334-5, pi. 13 fig. 3, text-fig. 3. Middle Jurassic 

England. 
Gonyaulacysta tvetzeli (Lejeune-Carpentier) Sarjeant, comb, nov., =Gonyaulax 

wetzeli Lejeune-Carpentier, 1939 ; 525-9, text-figs. 1-2. Upper Cretaceous, 

Germany. 
Gonyaulacysta whitei Sarjeant, 1966b ; 126-8, pi. 14 fig. 2, text-fig. 32. Upper 

Cretaceous, England. 

Genus LEPTODINIUM Klement i960 
emend. Wall 1967, emend. 
i960 Leptodinium gen. nov. Klement : 45. 

1965 Leptodinium Klement ; Norris & Sarjeant : 37. 

1966 Leptodinium Klement ; Loeblich & Loeblich : 38. 
1966b Leptodinium Klement ; emend. Sarjeant : 133-4. 

1967 Leptodinium Klement ; emend. Wall : 104. 

Emended diagnosis. Proximate dinoflagellate cysts, spheroidal, ovoidal, ellip- 
soidal or polyhedral, with reflected tabulation 3-4', o-ia, 6", 6c, 5-6'", ip, 0-1 p. v., 
1"", o-x s. Apical, median and antapical horns lacking. Cingulum strongly or 
weakly helicoid, laevorotatory ; cingular plates well or poorly marked. Sulcus 
generally but not constantly extending onto epitract, undivided or subdivided into 



1-- APPENDIX TO "STUDIES ON MESOZOIC 

a variable number of small plates. Rarely, an apical or an antapical pericoel may 
be present (but not both) ; the two shell layers are otherwise in continuous contact. 
Sutures typically marked by ridges or low crests (perforate or imperforate), without 
spines or denticles. Height of crests always less (and typically markedly less) than 
£ of shell width. A precingular single-plate archaeopyle, formed by loss of plate 3", 
is developed, the operculum typically becoming wholly detached ; in some speci- 
mens, the archaeopyle may not be developed. Surface of periphragm smooth, 
granular, or punctate. Forms with nodose or reticulate surface have not been 
encountered and forms with crest spines or with general spine cover are excluded. 

Type species. Leptodinium subtile Element, i960 ; 46-47, pi. 6 figs. 1-4, text- 
figs. 23-24. Upper Jurassic (Kimmeridgian), Germany. 

Remarks. The diagnosis here formulated is an expansion of that given by Wall 
(1967) : it differs in being more detailed and in permitting the inclusion of forms 
showing differentiation of the ventral surface into plates. Species with an apical 
horn are allocated to Gonyaulacysta ; species with sutures marked by lines of high 
spines are placed in Hystrichogonyaulax gen. no v. ; species with a general spine 
cover are placed in the genus Acanthaulax. The currently known range of the 
genus Leptodinium, as here defined, is Upper Jurassic to Recent. 

Other species. 
Leptodinium aceras (Eisenack) Sarjeant, comb, nov., =Gonyaulax aceras 

Eisenack, 1958 ; 391-2, pi. 21 figs. 1-2. Lower Cretaceous, Germany. 
Leptodinium aculeatum Wall, 1967 ; 104-5, pi. 14 figs. 18-19, text-figs. 3C, 3D. 

Pleistocene — Recent, Yucatan Basin, Caribbean Sea. 
Leptodinium alectrolophum Sarjeant, 1966b ; 134-5, pi. 15 figs. 3-6, text-fig. 34. 

Lower Cretaceous, England. 
Leptodinium amabilis (Deflandre) Sarjeant, comb, nov., =Gonyaulax amabilis 

Deflandre, 1939 ; 143, pi. 6 fig. 8. Upper Jurassic, France. 
Leptodinium arcuatum Element, i960 ; 48, pi. 6 figs 5-6. Upper Jurassic, 

Germany. 
Leptodinium clathratum (Cookson & Eisenack) Sarjeant, comb, nov., =Gony- 

aulax clathrata Cookson & Eisenack, 1960b ; 246-7, pi. 37 fig. 5, text-fig. 2. 

Upper Jurassic, Australia. 
}Leptodinium crassinervum (Deflandre) Sarjeant, comb, nov., =Palaeoperi- 

dinium crassinervum Deflandre, 1939 ; 144, pi. 6 fig. 5. (Transfer of this 

species to Gonyaulacysta was proposed by Sarjeant, 1967 ; 248-9). Upper 

Jurassic, France. 
Leptodinium delicatum (Davey) Sarjeant, comb, nov., ^Gonyaulacysta delicata 

Davey, 1968a ; 123-4, pi- 1 > fig s - 7> 8, text-figs. ioA,B. Upper Cretaceous, 

Saskatchewan, Canada. 
Leptodinium eumorphum (Cookson & Eisenack, 1960b ; 246, pi. 37 figs. 1-3, 

text-fig. 3) Eisenack, 1961 ; 324. Upper Jurassic, Australia. 
Leptodinium freakei (Sarjeant) Sarjeant, comb, nov., =Gonyaulax freakei 

Sarjeant, 1963b ; 85-6, pi. 1 figs. 1-3. Upper Jurassic, England. 



AND CAINOZOIC DINOFLAGELL ATE CYSTS " 13 

Leptodinium maculatum Cookson & Eisenack, 1961 ; 40, pi. 2 figs. 5-6. PUpper 

Eocene, Rottnest Island, Australia. 
Leptodinium margaritiferum (Cookson & Eisenack) Sarjeant, comb. nov. 

=Gonyaulax margaritifera Cookson & Eisenack, 1960a ; 5-6, pi. 2 figs. 1-2 

text-fig. 1. Upper Cretaceous, Western Australia. 
Leptodinium membranigerum Gerlach, 1961 ; 162-165, pi. 26 figs. 1-4, 7 

text-figs 4,5. Oligocene-Miocene, Germany. 
Leptodinium millioudi (Sarjeant) Sarjeant, comb, nov., =Gonyaulax millioudi 

Sarjeant, 1963b ; 86-88, pi. 1 figs. 4-7. Upper Jurassic, Switzerland. 
Leptodinium mirabile Element, i960 ; 48-50, pi. 6 figs. 7-10, text-fig. 25-7 

Upper Jurassic, Germany. 
}Leptodinium mosaicum (Downie) Sarjeant, comb, nov., =Palaeoperidinium 

mosaicum Downie, 1957 ; 424, pi. 20 fig. 7, text-fig. 2f. (Transfer of this 

species to Gonyaulacysta was proposed, as a provisional measure, by Sarjeant 

1967 ; 253). Upper Jurassic, England. 
Leptodinium paradoxum Wall, 1967 ; 106-7, pi- T 5 fig s - 5 _ 8, text-figs. 2, 3A, 3B. 

Miocene — Recent, Yucatan Basin, Caribbean Sea. 
}Leptodinium pilum (Gocht) Sarjeant, comb, nov., =Palaeoperidinium pilum 

Gocht, 1959 ; 56-7, pi. 6 fig. 14, pi. 8 fig. 8. (Transfer of this species to Gony- 
aulacysta was proposed, as a provisional measure, by Sarjeant, 1967 ; 255). 

Lower Cretaceous, Germany. 
Leptodinium porosum (Lejeune-Carpentier) Sarjeant, comb, nov., =Gonyaulax 

porosa Lejeune-Carpentier, 1946 ; 193. 196, text-fig. 6. Upper Cretaceous, 

Belgium. 
Leptodinium sphaericum Wall, 1967 ; 108, pi. 15 figs. 11-15, text-fig. 2a-c. 

Pleistocene — Recent, Yucatan Basin, Caribbean Sea. 
Leptodinium strialatum Wall, 1967 ; 107-8, pi. 15 figs. 9-10, text-fig. 5. 

Miocene — Recent, Yucatan Basin, Caribbean Sea. 
Leptodinium striatum (Clarke & Verdier) Sarjeant, comb, nov., = Gonyaulacysta 

striata Clarke and Verdier, 1967 ; 31-32, pi. 4 figs. 11-13, pi. 5 fig. 15, text-fig. 

12. Upper Cretaceous, England. 

Genus HYSTRICHOGONYA ULAX gen. nov. 

Derivation of name. In reference to the Gonyaulax-type tabulation exhibited, 
and to the presence of spines on the sutures. 

Diagnosis. Proximate dinoflagellate cysts, spheroidal, ovoidal, ellipsoidal or 
polyhedral, with the reflected tabulation 3-4', o-ia, 6", 6c, 5-6'", ip, 0-1 p.v., 
1"", o-x s. Apical, median and antapical horns lacking. Cingulum strongly or 
weakly helicoid, laevorotatory ; cingular plates well or poorly marked. Sulcus 
generally but not constantly extending onto the epitract, undivided or subdivided 
into a variable number of small plates. Rarely, an apical or an antapical pericoel 
may be present (but not both) ; the two shell layers are otherwise in continuous 
contact. Sutures marked by lines or low ridges from which arise isolated spines ; 
the length of spines may vary according to position on the test (e.g. the spines 



14 APPENDIX TO "STUDIES ON MESOZOIC 

ringing the antapex may be longer than the others), or may be relatively constant. 
The spines may be simple or may bifurcate or ramify near the tips : their length is 
constantly less than £ of the longest shell cross-measurement. A precingular 
single-plate archaeopyle, formed by loss of plate 3", is developed. Surface of peri- 
phragm smooth, granular or punctate. Forms with a nodose or reticulate surface 
have not, to date, been encountered : those with a general spine cover are excluded. 

Type species. Hystrichogonyaulax cornigera (Valensi) Sarjeant, comb. 

nov., =Gonyaulax cornigemm (sic) Valensi, 1953 ; 27, pi. 1 figs. 4, 8, 10, pi. 2 

figs. 1-2, pi. 13 fig. 5, text-fig. 2a. Middle Jurassic (Upper Bathonian), France. 
Other Species. Hystrichogonyaulax nealei (Sarjeant) Sarjeant, comb, nov., 

= Gonyaulax nealei Sarjeant, 1962 ; 480-1, pi. 69 fig. 1, text-fig. 2. Upper 

Jurassic, England. 
Remarks. This new genus corresponds to Leptodinium in its general morphology, 
differing in the possession of long sutural spines instead of low crests. It is most 
abundant in the Middle Jurassic and is characteristically numerous in Northwest 
European Bathonian sediments : the total known range is Middle to lower Upper 
Jurassic. On morphological grounds, it might be visualized as possibly ancestral to 
the genus Gonyaulacysta (which includes the species G. cladophora, with similar 
sutural spines but with an apical horn) and to the genus Leptodinium, by loss of the 
sutural spines ; at present, however, this must be regarded as a speculation only. 



Other generic reallocations 

Dichadogonyaulax pannea (Norris) Sarjeant, comb, nov., = Leptodinium panneum 

Norris, 1965 ; 796-8, figs. 3, 10-13. Upper Jurassic, England. 
Dichadogonyaulax schizoblata (Norris) Sarjeant, comb, nov., ^Leptodinium 

schizoblatum Norris, 1965 ; 798-800, figs. 4-5, 14-17. Upper Jurassic, 

England. 
}Litosphaeridium striatoconus (Deflandre & Cookson) Sarjeant, comb, nov., 

=Hystrichosphaeridium striatoconus Deflandre & Cookson, 1955 ; 275-6, 

pi. 2, fig. 10, text-fig. 36 (Transferred to Baltisphaeridium by Downie & Sarjeant 

1963 ; 92). Upper Cretaceous, Australia. 
Meiourogonyaulax bulloidea (Cookson & Eisenack) Sarjeant, comb, nov., 

= Gonyaulax bulloidea Cookson & Eisenack, 1960b ; 247, pi. 37 fig. n text-fig. 

4. Upper Jurassic, Western Australia. 
Meiourogonyaulax caytonensis (Sarjeant) Sarjeant, comb, nov., =Gonyaulax 

caytonensis Sarjeant, 1959 ; 330-2, pi. 13 fig. 1, text-fig. 1. Middle Jurassic, 

England. 
? Meiourogonyaulax cristulata (Sarjeant) Sarjeant, comb, nov., —Gonyaulax 

cristulata Sarjeant, 1959 ; 332-4, pi. 13 fig. 2, text-fig. 2. Middle Jurassic, 

England. 
Meiourogonyaulax decapitata (W. Wetzel) Sarjeant, comb, nov., =Gonyaulax 

decapilata W. Wetzel, 1966 ; 869, pi. 16 figs 7a-b. Middle Jurassic, Germany. 



AND CAINOZOIC DINOFLAGELLATE CYSTS" 15 

Meiourogonyaulax superornata (W. Wetzel) Sarjeant, comb, nov., =Gonyaulax 
superornata W. Wetzel, 1966 ; 869-870, pi. 16 figs 8a-b. Middle Jurassic, 
Germany. 

Polysphaeridium belgicum Sarjeant, sp. nov., = Hystrichosphaeridium fluctuans 
sensu Pastiels, 1948 ; 40, pi. 3 fig. 16, non Eisenack, 1938 ; 230-1, pi. 16 fig. 1 
(Pastiels wrongly cites this as Eisenack 1937). Holotype : the specimen 
figured by Pastiels, 1948 ; pi. 3 fig. 16. Dimensions : shell 30 x 35[jl, appen- 
dages 12 [x long, overall span 60 [x. Eocene — Artesian well, Gand, Belgium. 

Psaligonyaulax apatela (Cookson & Eisenack) Sarjeant, comb, nov., =Scrini- 
odinium apatelum Cookson & Eisenack, 1960b ; 249, pi. 37 figs. 12-13. Upper 
Jurassic, Australia. 

Psaligonyaulax simplicia (Cookson & Eisenack) Sarjeant, comb, nov., =Rottnestia 
simplicia Cookson & Eisenack, 1961 ; 42, 44, pi. 2 figs. 3-4, text-figs. 1 e-f. 
Eocene, Rottnest Island, Australia. 

Rhaetogonyaulax chaloneri (Sarjeant), comb, nov., = Gonyatdax chaloneri 
Sarjeant, 1963a ; 354, text-figs. 2 (right), 3. Upper Triassic, England. 



IV. GENERIC REALLOCATIONS PROPOSED JOINTLY BY 
R. J. DAVEY C. DOWNIE W. A. S. SARJEANT & G. L. WILLIAMS 

Areoligera galea (Maier) Davey, Downie, Sarjeant & Williams, comb, nov., 
= Galea galea Maier, 1959 ; 306, pi. 29 fig. 4. (Transferred to Baltisphaeridium 
by Sarjeant, 1964 ; 176). Oligocene, Germany. 

Areoligera lychnea (Maier) Davey, Downie, Sarjeant & Williams, comb, nov., 
=Galea lychnea Maier, 1959 ; 310, pi. 30 fig. 6. (Transferred to Baltisphaeri- 
dium by Sarjeant, 1964 ; 176). Miocene, Germany. 

Areoligera twistringensis (Maier) Davey, Downie, Sarjeant & Williams, comb, 
nov., =Galea twistringensis Maier, 1959 ; 308-9, pi. 30 figs. 3-4. (Transferred 
to Baltisphaeridium by Sarjeant, 1964 ; 176). Oligocene, Germany. 

Cleistosphaeridium ashdodense (Rossignol) Davey, Downie, Sarjeant and 
Williams, comb, nov., = Hystrichosphaeridium ashdodense Rossignol, 1962 ; 
132, pi. 2 fig. 2. (Transferred to Baltisphaeridium by Downie & Sarjeant, 1964; 
87. According to Wall 1967 ; 109, this species is a synonym of Lingulodinium 
machaerophorum). Quaternary, Israel. 

? Cleistosphaeridium danicum (W. Wetzel) Davey, Downie, Sarjeant & Williams, 
comb, nov., = Areoligera danica W. Wetzel, 1952 ; 396-7, pi. A fig. 5, text-fig. 
8. (Transferred to Hystrichosphaeridium by W. Wetzel, 1955 ; 34 ; transferred 
to Baltisphaeridium by Downie and Sarjeant, 1963 ; 91). Paleocene, Denmark. 

Cleistosphaeridium echinoides (Maier) Davey, Downie, Sarjeant & Williams, 
comb, nov., = Hystrichosphaeridium echinoides Maier, 1959 ; 318-19, pi. 32 
figs. 5-6. (Transferred to Baltisphaeridium by Downie & Sarjeant, 1963 ; 91). 
Oligocene, Germany. 



16 APPENDIX TO "STUDIES ON MESOZOIC 

Cleistosphaeridium ehrenbergi (Deflandre) Davey, Downie, Sarjeant & Williams, 
comb, nov., = Hystrichosphaeridium ehrenbergi Deflandre, 1947 ; text-fig. 1 
no. 5. (Transferred to Baltisphaeridium by Sarjeant, 1961 ; 103). Middle 
Jurassic, France. 

Cleistosphaeridium leve (Maier) Davey, Downie, Sarjeant & Williams, comb, nov., 
=Galea levis Maier, 1959 ; 308, pi. 30 figs. 1-2 (Transferred to Baltisphaeridium 
by Sarjeant, 1964 ; 176). Oligocene-Miocene, Germany. 

Cleistosphaeridium lumectum (Sarjeant) Davey, Downie, Sarjeant & Williams, 
comb, nov., = Baltisphaeridium lumectum Sarjeant, i960 ; 139-40, pi. 6, fig. 1, 
text-fig. 2. Upper Jurassic, England. 

Cleistosphaeridium multifurcatum (Deflandre) Davey, Downie, Sarjeant & 
Williams, comb, nov., = Hystrichosphaeridium multifurcatum Deflandre, 1937 ; 
76, pi. 16 figs. 1-3 (Transferred to Baltisphaeridium by Klement, i960 ; 59). 
Upper Cretaceous, France. 

? Cleistosphaeridium oligacanthum (W. Wetzel) Davey, Downie, Sarjeant & 
Williams, comb, nov., = Hystrichosphaeridium oligacanthum W. Wetzel, 1952 ; 
402-3, pi. A fig. 8, text-figs. 21-2 (Transferred to Baltisphaeridium by Downie & 
Sarjeant, 1963 ; 91). Paleocene, Baltic Region. 

Cleistosphaeridium pectiniforme (Gerlach) Davey, Downie, Sarjeant & Williams, 

comb, nov., = Baltisphaeridium pectiniforme Gerlach, 1961 ; 195, pi. 28 fig. 14, 

text-fig. 18. Oligocene, Germany. 
Cleistosphaeridium poly trichum (Valensi) Davey, Downie, Sarjeant & Williams, 

comb, nov., = Hystrichosphaeridium polytrichum Valensi, 1947 ; 818, text-fig. 4 

(Transferred to Baltisphaeridium by Sarjeant, 1959 ; 339). Middle Jurassic, 

France. 
^Cleistosphaeridium spiralisetum (de Wit) Davey, Downie, Sarjeant & Williams, 

comb, nov., = Hystrichosphaeridium spiralisetum de Wit, 1943 ; 383, text-figs. 

2, 11 (Transferred to Baltisphaeridium by Downie & Sarjeant, 1964 ; 97). 

Upper Cretaceous, Netherlands. 
Cleistosphaeridium tiara (Klumpp) Davey, Downie, Sarjeant & Williams, comb. 

nov., = Hystrichosphaeridium tiara Klumpp, 1953 ; 390-1, pi. 17 figs. 8-10 

(Transferred to Baltisphaeridium by Downie & Sarjeant, 1963 ; 92). Eocene 

Germany. 
Cleistosphaeridium tribuliferum (Sarjeant) Davey, Downie, Sarjeant & Williams, 

comb, nov., = Baltisphaeridium tribuliferum Sarjeant, 1962 ; 487-8, pi. 70 fig. 

4, text-figs. 6c, 7. Upper Jurassic, England. 
Exochosphaeridium palmatum (Deflandre & Courteville) Davey, Downie, 

Sarjeant & Williams, comb, nov., = Hystrichosphaeridium palmatum Deflandre & 

Courteville, 1939 ; 101-2, pi. 3 fig. 1 (Transferred to Baltisphaeridium by Downie 

& Sarjeant, 1963 ; 91). Upper Cretaceous, France. 

? Exochosphaeridium pseudhystrichodinium (Deflandre) Davey, Downie, 

Sarjeant & Williams, comb, nov., = Hystrichosphaeridium pseudhystrichodinium 



AND CAINOZOIC DINOFLAGELLATE CYSTS " 17 

Deflandre, 1937 ; 73, pi. 15 figs. 3-4 (Transferred to Baltisphaeridium by Downie 
& Sarjeant, 1963 ; 93). Upper Cretaceous, France. 

Prolixosphaeridium mixtispinosum (Klement) Davey, Downie, Sarjeant & 
Williams, comb, nov., = Baltisphaeridium mixtispinosum Klement, i960 ; 
58-9, pi. 6 figs. 17-19. Upper Jurassic, Germany. 

Prolixosphaeridium parvispinum (Deflandre) Davey, Downie, Sarjeant & 
Williams, comb, nov., = Hystrichosphaeridium xanthiopyxides var. parvispinum 
Deflandre, 1937 ; 29, pi. 16 fig. 5 (Raised to specific rank, as Hystrichosphaeri- 
dium parvispinum, by Cookson & Eisenack, 1958 ; 45 ; transferred to Balti- 
sphaeridium by Klement, i960 ; 59). Upper Cretaceous, France. 

? Prolixosphaeridium xanthiopyxides (O. Wetzel) Davey, Downie, Sarjeant & 
Williams, comb, nov., =Hystrichosphaera xanthiopyxides O. Wetzel, 1933, 
44-5 ; pi. 4 fig. 25 (Transferred to Hystrichosphaeridium by Deflandre, 1937 ; 
77 ; transferred to Baltisphaeridium by Klement, i960 ; 59). Upper Creta- 
ceous, Germany. 

Systematophora placacantha (Deflandre & Cookson) Davey, Downie, Sarjeant & 
Williams, comb, nov., = Hystrichosphaeridium placacanthum Deflandre & 
Cookson, 1955 ; 276-7, pi. 9 figs. 1-3 (Transferred to Baltisphaeridium by 
Downie & Sarjeant, 1963 ; 92). Miocene, Australia. 



V. GENERIC REALLOCATIONS PROPOSED BY 
G. L. WILLIAMS & C. DOWNIE 

Adnatosphaeridium aemulum (Deflandre) Williams & Downie, comb, nov., 
= Hystrichosphaeridium aemulum Deflandre, 1938 ; 187-9, P^ 9 %• 12 > pi- I0 
figs. 5-8, pi. 11 figs. 1-7 (Transferred to Cannosphaeropsis by Deflandre, 1947a ; 
1574). Upper Jurassic, France. 

Adnatosphaeridium caulleryi (Deflandre) Williams & Downie, comb, nov., 
= Hystrichosphaeridium caulleryi Deflandre, 1938 ; 189, pi. 11 figs. 2-3 (Trans- 
ferred to Cannosphaeropsis by Deflandre, 1947 ; 1574). Upper Jurassic, 
France. 

Adnatosphaeridium filamentosum (Cookson & Eisenack) Williams & Downie, 
comb, nov., = Cannosphaeropsis fdamentosa Cookson & Eisenack, 1958 ; 47-8, 
pi. 7 figs. 8-9, pi. 8 figs. 1-2. Middle-Upper Jurassic, Australia. 

Adnatosphaeridium filiferum (Cookson & Eisenack) Williams & Downie, comb, 
nov., =Cannosphaeropsis utinensis var. filifera Cookson & Eisenack, 1958 ; 
46, pi. 7 fig. 4 (Raised to specific rank, as Cannosphaeropsis filifera, by Cookson 
& Eisenack, 1960a ; 8-9). Upper Cretaceous, Australia. 

Hystrichokolpoma clavigera (Deflandre) Williams & Downie, comb, nov., 
= Hystrichosphaeridium clavigerum Deflandre, 1937 ; 71, pi. 14 figs. 1-2 
(Transferred to Baltisphaeridium by Downie & Sarjeant, 1963 ; 91). Upper 
Cretaceous, France. 



[8 APPENDIX TO "STUDIES ON MESOZOIC 

VI. TAXONOMIC REVISIONS MADE BY OTHER AUTHORS 

Taxonomic revisions made by other authors in the period since publication of our 
' Studies on Mesozoic and Cainozoic dinoflagellate cysts ' have caused the omission, 
from the preceding sections, of a number of species transferred to new genera in the 
earlier work without new combinations for them being validly published. It is felt 
that these should be briefly listed here, in order to provide comprehensive coverage. 

(a) The species Hystrichosphaeridium zoharyi Rossignol, 1962, whose transfer to 
the genus Polysphaeridium was tentatively proposed by Davey & Williams 
(1966b ; 95), has been made type for a new genus, Hemicystodinium, by Wall, 
(1967 ; no) on the basis of its development of an epitractal archaeopyle. 

(b) The species Hystrichosphaeridium israelianum Rossignol, 1962 (placed in the 
genus Baltisphaeridium by Downie and Sarjeant, 1964) and Hystrichosphaeri- 
dium centrocarpum Deflandre and Cookson, 1955 (placed in the genus Balti- 
sphaeridium by Gerlach, 1961), were transferred to the genus Cleistosphaeri- 
dium by Davey, Downie, Sarjeant & Williams (1966 ; 170). Both have been 
placed in a new genus, Operculodinium, by Wall (1967 ; no-n), H. centro- 
carpum being chosen as type. This genus resembles Exochosphaeridium 
Davey, Downie, Sarjeant & Williams (1966 ; 165) in its development of a 
single-plate precingular archaeopyle, differing in the apparent absence of an 
enlarged apical process, and in the presence of striations on the bases of the 
processes. 

(c) The species Hystrichosphaeridium machaerophorum Deflandre & Cookson, 1955 
(placed in the genus Baltisphaeridium by Downie & Sarjeant, 1963), was 
transferred to the genus Cleistosphaeridium by Davey, Downie, Sarjeant & 
Williams (1966 ; 165). It has been made the type of a new genus, Lingulo- 
dinium, by Wall (1967 ; 109-10), on the basis of its possession of a precingular 
archaeopyle formed by loss of the equivalents of four or five plate areas. 

(d) In three instances, the proposed type species of new genera formulated in our 
earlier work were not initially validly transferred to those genera (I. C.B.N. 
Art. 33) and were subsequently validly transferred by Loeblich & Loeblich, 
(1968). These are : Dichadogonyaulax culmula (Norris, 1965) Leoblich & Loe- 
blich, 1968 ; 211 [= Dichadogonyaulax culmula (Norris, 1965) Sarjeant, 1966b ; 
153, nom. nud.] ; Duosphaeridium nudum (Cookson, 1965) Loeblich & Loe- 
blich, 1968 ; 211 [= Duosphaeridium nudum (Cookson, 1965) Davey & Williams, 
1966b ; 97, nom. nud.] ; and Rhaetogonyaulax rhaetica (Sarjeant, 1963) 
Loeblich & Loeblich, 1968 ; 212 [= Rhaetogonyaulax rhaetica (Sarjeant, 1963), 
1966 ; 97, nom. nud.]. 

(e) As a result of a redefinition of the genus Cribroperidinium Neale & Sarjeant 
(1962), proposed by Davey (1968a ; 125), the species Gonyaulax edwardsi 
Cookson & Eisenack 1958, Gonyaulax muderongensis Cookson & Eisenack 
1958, and Gonyaulax orthoceras Eisenack 1958 sensu stricto (i.e. excluding 
G. parorthoceras Davey 1968b), whose reallocation to Gonyaulacysta was 
proposed by Sarjeant (1966 ; 130 ; 131 ; 121-3), are now transferred to 
Cribroperidinium (Davey 1968a ; 128). 



AND CAINOZOIC DINOFLAGELLATE CYSTS " 19 

Davey {op. cit.) also validly published the following combinations : Cleistos- 
phaeridium multifurcatum (Deflandre, 1937), Cleistosphaeridium polypes 
(Cookson & Eisenack, 1962), Cleistosphaeridium pseudhystrichodinium 
(Deflandre, 1937) [wrongly spelled pseudohystrichodinium in all citations], 
Hystrichokolpoma ferox (Deflandre, 1937) emend., Oligosphaeridium 
anthophorum (Cookson & Eisenack, 1958) and Oligosphaeridium reniforme 
(Tasch, in Tasch, McClure & Oftedahl, 1964). He considered no change in 
the generic allocation of Hystrichosphaeridium difficile Manum & Cookson, 
1964, to be necessary. 

(f) Two recent large papers exhibit a high degree of taxonomic overlap with our 
1966 volume. One of these (Morgenroth, 1966) has priority of publication by 
one month ; it is hoped that the systematic problems created will be sorted 
out in a later paper. The second (Clarke & Verdier, 1967) does not have 
priority : a short note, giving the resulting synonymy, has recently been 
published (Clarke, Davey, Sarjeant & Verdier, 1968). 

(g) Pending a restudy of its holotype, no proposal of generic transfer is here made 
respecting Hystrichosphaeridium tridactylites Valensi, 1955a. 

(h) A new name, Acanthaulax, was proposed to replace the invalid junior hononym 
Acanthogonyaulax by Sarjeant, 1968, and all constituent species were trans- 
ferred. 

VII. ERRATA AND CURATORIAL AMENDMENTS 

The following errata have been noted and merit correction : 

p. 28 line 20. For ' nomen nudum ', read ' nomen oblitum '. 

p. 63 line 8. Revise to read ' V. 51708 (1) '. 

p. 65 line 5. Revise to read ' PL 7 fig. 9 ; pi. 8 fig. 6 ' 

p. 70 Delete parentheses from : ' Maier 1959 ' (lines 15 and 24) ; 'Eisenack 

and Cookson, i960 ' (line 18) ; ' Deunff, 1961 ' (line 20) ; and ' Macko, 

1957 ' (line 22). 
p. 75 line 1. Revise to read ' V. 51709 (3) '. 

line 6. Revise to read ' V. 51709 (1) '. 
p. 78 Delete last sentence of ' Remarks '. 

p. 80 Text-fig. 16. ip and 1'" should be interchanged in both drawings, 
p. 92 line 4. Alter to read ' Polysphaeridium subtile sp. nov.' 
p. 95 line 12. Alter to read ' (Weiler, 1956) '. 

p. 100 line 33. Alter to read ' Homotryblium tenuispinosum sp. nov.' 
p. 133 lines 15-16. Insert between these lines ' Plate 22 fig. 2.' 

line 22. Alter to read ' heslertonensis' . 
p. 140 line 20. For ' junior homonym ' read ' junior synonym '. 
p. 144 line 13. Revise to read ' V. 51710 (1) '. 
p. 147 line 13. Alter to read ' Xiphophoridium alatum sp. nov.' 

line 15. Correct page number to ' 487 '. 
p. 154 line 20. Alter to read ' Wanaea spectabilis (Deflandre & Cookson) , 

Cookson & Eisenack, 1958 '. 



2o APPENDIX TO "STUDIES ON MESOZOIC 

p. 1 66 line 26. Alter to read ' Cleistosphaeridium diversispinosum sp. nov.' 

p. 166 line 16. Alter to read ' Exochosphaeridium '. 

p. 167 line 5. Alter to read ' Cleistosphaeridium ' . 

p. 170 line 21. Delete ' Miocene, Australia ': insert ' Quaternary, Israel '. 

pp. 182-198. Throughtout this section, the left and right antapical horns are 

interchanged in the descriptions. It is the right horn that is typically 

reduced or absent, 
p. 195 lines 20, 21. Alter to read ' solida 

line 38. Alter to read ' solidum '. 
p. 197 line 28. Alter to read ' Sub-Genus WETZELIELLA (RHOMBODI- 

NIUM) (Gocht) Alberti, 1961 '. 
p. 201 line 29. Alter to read ' Paranetr elytron 
p. 219 line 10. Alter to read ' Membranilarnacia '. 
p. 225 line 3. Alter to read : ' 1948 Membranilarnax pterospermoides O. 

Wetzel, 1933, of Pastiels '. 
p. 245 Index. Insert to give : ' Heslertonia heslertonensis 133. pi. 22 fig. 2 '. 

Caption for Plate 3. Explanations of Figures 3 and 4 should be transposed, 

and altered to read ' Cordosphaeridium '. 

Caption for Plate 9 fig. 6. Alter to read : ' 103-25 m'. 

fig. 7. ' Holotype ' should read : ' Paratype '. Figure 
shows left-to-right reversal. 

Caption for Plate 10 fig. 4. Alter to read : ' V. 51708 (1) '. 

Caption for Plate 11 fig. 9. Revise to read : ' disjunction '. 

Caption for Plate 13 fig. 1. Alter to read : ' V. 51425 (2) '. 

Caption for Plate 15 figs. 1-2. Correct to read : ' Gonyaulacysta '. 
fig. 5. Alter to read ' V. 51725 (1) '. 
For curatorial reasons, it is proposed that slides containing a single specimen 
should not have a number 1 in parentheses. This proposal necessitates the following 
changes : 

V. 51715 (1) becomes V. 51715 (p. 213, line 10). 

V. 51720 (1) becomes V. 51720 (caption for Plate 23 fig. 6). 

V. 51721 (1) becomes V. 51721 (p. 209 line 26 : caption for Plate 22 fig. 5). 

V. 51726 (1) becomes V. 51726 (p. 210 line 6 ; caption for Plate 21 fig. 4). 

V. 51733 (1) becomes V. 51733 (p. 207 line 3 ; caption for Plate 21 fig. 1). 

V. 51735 (1) becomes V. 51735 (p. 161 line 15 ; caption for Plate 9 fig. 6). 

V. 51736 (1) becomes V. 51736 (p. 163 fig. 5 ; caption for Plate 9 fig. 8). 



VIII. REFERENCES 

Alberti, G. 1961. Zur Kenntnis mesozoischer und alttertiarer Dinoflagellaten und Hystri- 
chosphaerideen von Nord — und Mitteldeutschland sowie einigen anderen europaischen 
Gebieten. Palaeontographica, Cassel, Stuttgart, 116A : 1-58, pis. 1-12. 

Brosius, M. 1963. Plankton aus dem nordhessischen Kasseler Meeressand (Oberoligozan). 
Z. dt. geol. Ges., Berlin, 114, 1 : 32-56, pis. i-8, text-figs. 1, 2, pis. 1, 2. 



AND CAINOZOIC DINOFLAGELLATE CYSTS" 21 

Clarke, R. F. A., Davey, R. J., Sarjeant, W. A. S. & Verdier, J. -P. 1968. A note on the 
nomenclature of some Upper Cretaceous and Eocene dinoflagellate taxa. Taxon, Utrecht, 
17 : 181-3. 

Clarke, R. F. A. & Verdier, J. -P. 1967. An investigation of microplankton assemblages 
from the Chalk of the Isle of Wight, England. Verh. K. ned. Akad. Wet., Amsterdam, 
24 (3), 1-96, pis. 1-17. 

Cookson, I. C. 1965. Cretaceous and Tertiary microplankton from south-eastern Australia. 
Proc. R. Soc. Vict., Melbourne, n.s., 78 : 85-93, pis. 9-1 1. 

Cookson, I. C. & Eisenack, A. 1958. Microplankton from Australian and New Guinea 
Upper Mesozoic sediments. Proc. R. Soc. Vict., Melbourne, 70, 1 : 19-79, pis. 1-12. 

, 1960a. Microplankton from Australian Cretaceous sediments. Micropaleontology, 

New York, 6, 1 : 1-18, pis. 1-3. 

, 1960b. Upper Mesozoic microplankton from Australia and New Guinea. Palae- 
ontology, London, 2, 2 : 243-61, pis. 37-39. 

, 1961. Tertiary microplankton from the Rottnest Island Bore, Western Australia. 

/. Proc. R. Soc. W. Aust., Perth, 44 : 39-47, pis. 1-2, text-fig. 1. 

1962. Additional microplankton from Australian Cretaceous sediments. Micro- 



paleontology, New York, 8, 4 : 484-507, pis. 1-7. 
Davey, R. J. 1968a. Non-Calcareous Microplankton from the Cenomanian of England, 
northern France and North America. Part 1. Bull. Br. Mus. nat., London, 17, 3, 105- 
180, pis. I-II, 

1968b. Gonyaulacysta parorthoceras, a new species of dinoflagellate cyst. Palaeont. afr. 

Johannesburg, 17 : 1. 

Davey, R. J., Downie, C, Sarjeant, W. A. S. & Williams, G. L. 1966. Fossil dinoflagellate 

cysts attributed to Baltisphaeridium. Bull. Br. Mus. nat. Hist. Geol., London, Suppl. 3 : 

157-75. Pis. 2-3 (pars), 9 (pars), 11 (pars). 
Davey, R. J. & Williams, G. L. 1966a. The genera Hystrichosphaera and Achomospkaera. 

Bull. Br. Mus. nat. Hist Geol., London, Supp. 3 : 28-52, pis. 1, 2-5 (pars), 9 (pars), tab. 2. 
, 1966b. The genus Hystrichosphaeridium and its allies. Bull. Br. Mus. nat. Hist. 

Geol., London, Supp. 3 : 53-106, pis. 3-9 (pars), 10, 11 (pars), 12, tab. 3. 
Deflandre, G. 1935. Considerations biologiques sur les micro-organismes d'origine plancto- 

nique conserves dans les silex de la craie. Bull. biol. Fr. Belg., Paris, 69 : 213-44, pis. 5-9. 
1937- Microfossiles des silex cretaces 1 1 . Flagelles incertae sedis. Hystrichosphaeridees. 

Sarcodines. Organismes divers. Annls. PaUont., Paris, 26 : 51-103, pis. 8-18. 

1938. Microplankton des mers jurassiques conserve dans les marnes de Villers-sur-Mer 

(Calvados). Etude liminaire et considerations generates. Trav. Stn. Zool. Wimereux, 
Paris, 13 : 147-200, pis. 5-1 1, text-figs. 1-10. 

1939. Sur les dinoflagelles des schistes bitumineux d'Orbagnoux (Jura). Bull. Soc.fr. 

Microsc, Paris, 8, 4 : 141-5, pi. 6. 

1946a. Hystrichosphaerides 11. Especes du Secondaire et du Tertiaire. Fichier micro- 

paldont. ser. 6. Arch. Orig. Serv. Docum. C.N.R.S., no. 235, parts I-V, cards 860-1019. 

1946b. Remarques sur la systematique des Hystrichospheres. C.r. somm. Seanc. Soc. 

geol. Fr., Paris, 7 : no— 11. 

1947. Sur une nouvelle Hystrichosphere des silex cretaces et sur les affinities du genre 

Cannosphaeropsis O. Wetzel. C.r. hebd. Seanc. Acad. Sci., Paris, 224 : 1574-76, figs. 1-5. 

1964. Quelques observations sur la systematique et la nomenclature des dinoflagelles 

fossiles. Multicop. E.P.H.E. et illustration C.N.R.S., Paris : 1-8. 

Deflandre, G. & Cookson, I. C. 1955. Fossil microplankton from Australian late Mesozoic 
and Tertiary sediments. Aust. J. mar. Freshwat. Res., Melbourne, 6, 2 : 242-313, pis. 1-9. 

Deflandre, G. & Courteville, M. 1939. Note preliminaire sur les microfossiles des silex 
cretaces du Cambresis. Bull. Soc. fr. Microsc, Paris, 8 : 95-106, pis. 1-3. 

Downie, C. 1957. Microplankton from the Kimeridge Clay. Q. Jl. geol. Soc. Lond., 112 : 
4*3-34. P 1 - 20. 



22 APPENDIX TO "STUDIES ON MESOZOIC 

Downie, C. & Sarjeant, W. A. S. 1963. On the interpretation of some Hystrichosphere 

genera. Palaeontology. London, 6, 1 : 83-96. 
, 1964. Bibliography and index of fossil dinoflagellates and acritarchs. Mem. geol. 

Soc. Am., New York, 94 : 180 pp. 
Drugg, W. S. 1967. Palynology of the Upper Moreno Formation (late Cretaceous-Paleocene), 

Escarpado Canyon, California. Palaeontographica, Stuttgart, ser. B., 120 : 1— 71, pis. 1-9. 
Dupin, F. 1968. Deux nouvelles especes de Dinoflagelles du Jurassique d'Aquitaine. Cah. 

micropallont., Paris, ser 1, 8 : 1-5, pi. 1. 
Eisenack, A. 1938. Hystrichosphaerideen und verwandte Formen in baltischen Silur. 

Z. Geschiebeforsch., 14 : 1-30, pis. 1-4, text-figs. 1-7. 

1954- Mikrofossilien aus Phosphoriten des samlandischen Unter-Oligozans und fiber die 

Einheitlichkeit der Hystrichosphaerideen. Palaeontographica, Stuttgart, ser. A., 105 : 

49-95. p!s- 7-I 2 - 

1958. Mikroplankton aus dem norddeutschen Apt nebst einigen Bemerkungen iiber 

fossile Dinoflagellaten. Neues Jb. Geol. Paldont., Abh., Stuttgart, 106, 3 : 383-422, pis. 
21-7. 

1 961. Einige Erorterungen iiber fossile Dinoflagellaten nebst Ubersicht iiber die zur Zeit 

bekannten Gattungen. Neues Jb. Geol. Paldont., Abh., Stuttgart, 112, 3 : 281-324, pis. 33-7. 

Eisenack, A. & Cookson, I. C. i960. Microplankton from Australian Lower Cretaceous 

sediments. Proc. R. Soc. Vict., Melbourne, 72, 1 : 1-11, pis. 1-3. 
Eisenack, A. & Klement, K. W. 1964. Katalog der fossilen Dinoflagellaten, Hystricho- 

sphdren und verwandten Mikrofossilien. Stuttgart : E. Schweizerbart. 887 pp., 9 pis. 
Gerlach, E. 1 961. Mikrofossilien aus dem Oligozan und Miozan Nordwestdeutschlands, 

unter besonderer Berucksichtigung der Hystrichosphaerideen und Dinoflagellaten. Neues Jb. 

Geol. Paldont., Abh., Stuttgart, 112, 2 : 143-228, pis. 25-9, text-figs. 1-23. 
Gocht, H. 1959. Mikroplankton aus dem nordwestdeutschen Neokom 11. Paldont. Z., 

Berlin, 33, 1-2 : 50-89, pis. 3-8. 
Klement, K. W. i960. Dinoflagellaten und Hystrichosphaerideen aus dem Unteren und 

Mittleren Malm Sudwestdeutschlands. Palaeontographica Cassel, Stuttgart, A, 114 : 1-104, 

pis. 1-10. 
Klumpp, B. 1953. Beitrag zur Kenntnis der Mikrofossilien des Mittleren und Oberen Eozan. 

Palaeontographica, Cassel, Stuttgart, 103, A : 377-406, pis. 16-20, text-figs. 1-5. 
Lejeune-Carpentier, M. 1939. L'etude microscopique des silex (7 ieme Note). Un 

nouveau Peridinien cr6tacique, Gonyaulax wetzeli. Annls. Soc. giol. Belg., Liege, 62, 

10-11 : B525-9., text-figs, i, 2. 
1940. L'etude microscopique des silex (8 ieme Note). Systematique et morphologie 

des " Tubiferes ". Annls. Soc. giol. Belg., Liege, 63, 5 : B216-36, text-figs. 1-14. 

1941. L'etude microscopique des silex (9 ieme Note). Sur Hystrichosphaeridium 



hirsutum (Ehrenberg) et quelques formes voisines. Annls. Soc. giol. Belg., Liege, 63 (3) B, 

71-92. 
1946. L'etude microscopique des silex (12 ieme Note). Especes nouvelles ou 

douteuses de Gonyaulax. Annls. Soc. giol. Belg., Liege, 69, 4 : B187-97, figs. 1-5. 
Loeblich, A. R., Jnr. & Loeblich, A. R., III. 1966. Index to the genera, subgenera and 

sections of the Pyrrhophyta. Stud. Prop. Oceanogr., Miami, 3 : 94 pp. 
, 1968. Index to the genera, subgenera and sections of the Pyrrhophyta II. /. 

Paleont., Tulsa, 42 : 210-13. 
Maier, D. 1959. Planktonunterschungen in tertiaren und quataren marinen Sedimenten. 

Neues Jb. Geol. Paldont., Abh., Stuttgart, 107, 3 : 278-340, pis. 27-33. 
Manum, S. & Cookson, I. C. 1964. Cretaceous microplankton in a sample from Graham 

Island, Arctic Canada, collected during the second " Fram " expedition (1898-1902), with 

notes on the microplankton from the Hassel Formation, Ellef Ringnes Island. Skr. norske 

Vidensk-Akad., Oslo, n.s., 17 : 1-36, pis. 1-7. 



AND CAINOZOIC DINOFLAGELLATE CYSTS " 23 

Merrill, J. A. 1895. Fossil sponges of the flint nodules in the Lower Cretaceous of Texas. 
Bull. Mus. comp. Zool. Harv., Cambridge, Mass., 28, 1 : 1-26, pi. 1. 

Morgenroth, P. 1967. Mikrofossilien und Konkretionen des Nordwestdeutschen Unter- 
eozans. Palaeontographica, Stuttgart, ser. B, 119 : 1-53, pis. 1-11. 

Neale, J. W. & Sarjeant, W. A. S. 1962. Microplankton from the Speeton Clay of York- 
shire. Geol. Mag., London, 99, 5 : 439-58, pis. 19, 20. 

Norris, G. 1965. Archeopyle structures in Upper Jurassic dinoflagellates from southern 
England. N.Z. Jl. Geol. Geophys., Wellington, 8 : 792-806. 

Norris, G. & Sarjeant, W. A. S. 1965. A descriptive index of genera of fossil Dinophyceae 
and Acritarcha. Bull. geol. Surv. N.Z. Paleont., Wellington, 40. 72 pp. 

Pastiels, A. 1948. Contributions a l'etude des microfossiles de l'Eocene beige. Mim. Mus. 
r. Hist. nat. Belg., Bruxelles, 109 : 1-77, pis. 1-6. 

Philipott, A. 1949. Contributions a la paleontologie des silex cretaces. Trois nouveaux 
microfossiles. Bull. Soc. sclent. Bretagne, Rennes, 24 : 55-8, text-figs. 1-3. 

Pocock, S. A. J. 1962. Microfloral analysis and age determination of strata at the Jurassic- 
Cretaceous boundary in the Western Canada plains. Palaeontographica, Cassel, Stuttgart, 
111, B : 1-95, pis. 1-15. 

Reade, J. B. 1839. On some organic remains in the Flint of Chalk. Ann. Mag. nat. Hist., 
London, 2 : 191-8, pis. 8-9. 

Rossignol, M. 1962. Analyse pollinique de sediments marins Quaternaires en Israel 11. 
Sediments Pleistocenes. Pollen Spores, Paris, 4, 1 : 121-48, pis. 1, 2, tabs. 1, 2, map. 1. 

Sarjeant. W. A. S. 1959. Microplankton from the Cornbrash of Yorkshire. Geol. Mag., 
London, 96, 5 : 329-46, pi. 13. 

i960. New Hystrichospheres from the Upper Jurassic of Dorset. Geol. Mag., London 

97, 2 : 137-44, pl- 6, text-figs. 1-4. 

1961. Microplankton from the Kellaways Rocks and Oxford Clay of Yorkshire. Palae- 
ontology, London, 4, 1 : 90-118, pis. 13-15. 

1962. Microplankton from the Ampthill Clay of Melton, South Yorkshire. Palaeontology, 

London, 5, 3 : 478-97, pis. 69-70. 
1963a. Fossil dinoflagellates from Upper Triassic sediments. Nature, Lond., London, 

199, 4891 : 353-4, text-figs. 1-3. 

1963b. Two new Jurassic species of Gonyaulax (Dinophyceae). Revue MicropaUont., 

Paris, 6, 2 : 85-8, pi. 1. 

1964. Taxonomic notes on hystrichospheres and acritarchs. /. Paleont., Tulsa, 38 : 

173-7- 

1966a. The supposed " sponge spicules " of Merrill, 1895, from the Lower Cretaceous 

(Albian) of Texas. Breviora, Cambridge, Mass., 242, 1-15, pi. 1, text-fig. A. 

1966b. Dinoflagellate cysts with Gonyaulax-ty-pe tabulation. Bull. Br. Mus. nat. Hist. 

Geol., London, Supp. 3 : 107-56, pis. 13-16, tab. 4. 

1966c. Further dinoflagellate cysts from the Speeton Clay. Bull. Br. Mus. nat. Hist. 

Geol., London, Supp. 3 : 199-214, pis. 21-3, tab. 5. 

1967. The genus Palaeoperidinium Deflandre (Dinophyceae). Granapalynol., Stockholm, 

7 : 243-58. 

1968. Microplankton from the Upper Callovian and Lower Oxfordian of Normandy. 

Revue MicropaUont., Paris, 10 : 221-42, pis. 1-3. 

Tappan, H. & Loeblich, A. R., Jnr. 1967. Review : Studies on Mesozoic and Cainozoic 

dinoflagellate cysts. /. Paleont., Tulsa, 41 : 1030-33. 
Tasch, P., McClure, K. & Oftedahl, O. 1964. Biostratigraphy and taxonomy of a hystri- 

chosphere-dinoflagellate assemblage from the Cretaceous of Kansas. Micropaleontology , 

New York, 10 : 189-206, pis. 1-3. 
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region de Poitiers. Cr. hebd. Seanc. Acad. Sci., Paris, 225 : 816-8, figs. 1—8. 

1953. Microfossiles des silex du Jurassique moyen. Remarques petrographiques. 

M6m. Soc. giol. Fr., Paris, 68, 100 pp., 7 figs. 



24 APPENDIX TO "STUDIES ON MESOZOIC 

Yalensi, L. 1955a. Sur quelques micro-organismes des silex cretaces du Magdalenien de Saint- 
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1955b. Etude micropaleontologique des silex du Magdalenien de Saint-Amand (Cher). 

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I. Ges., Berlin, Jg. 1964, 116 : 867-74, pl s - I 5 _I 7- 



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R. J. Davey, B.Sc, Ph.D., F.G.S. 

Formerly of Bernard Price Institute for Palaeontological Research 

University of the Witwatersrand 

Johannesburg 

South Africa 

C. Downie, B.Sc, Ph.D., F.G.S. 
Dept. of Geology 
University of Sheffield 
England 

W. A. S. Sarjeant, B.Sc, Ph.D., F.G.S., F.L.S. 
Dept. of Geology 
University of Nottingham 
England 

G. L. Williams, B.Sc, Ph.D. 
Pan-American Petroleum Corp. 
Research Center 
Tulsa 
Oklahoma, U.S.A. 



J if- Printed in England by Staples Printers Limited at their Kettering, Northants, establishment 




PERMIAN TO PALAEOCENE 
CALCAREOUS ALGAE 

(DASYCLADACEAE) 
OF THE MIDDLE EAST 



G. F. ELLIOTT 



BULLETIN OF 

THE BRITISH MUSEUM (NATURAL HISTORY) 

GEOLOGY Supplement 4 

LONDON: 1968 






PERMIAN TO PALAEOCENE 



CALCAREOUS ALGAE 

(DASYCLADACEAE) 

OF THE MIDDLE EAST 



BY 

GRAHAM FRANCIS ELLIOTT 



BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Supplement 4 

LONDON: 1968 



THE BULLETIN OF THE BRITISH MUSEUM 

(natural history), instituted in 1949, is 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Supplement 4 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 



World List abbreviation 
Bull. Br. Mtis. not. Hist. (Geol.) 



© Trustees of the British Museum (Natural History) 1968 



TRUSTEES OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 

Issued 8 November, 1968 Price £5 2s. 6d. 



PERMIAN TO PALAEOCENE 
CALCAREOUS ALGAE 

(DASYCLADACEAE) 
OF THE MIDDLE EAST 

By GRAHAM FRANCIS ELLIOTT 



CONTENTS 

I. Introduction ....... 

II. Study and Classification of Fossil Dasyclad Algae 
III. Systematic Descriptions . 



acicularia d'Archiac 
A . antiqua Pia 
A . elongata Carozzi . 
A . (Briardina) sp. . 

acroporella Praturlon . 
A . assurbanipali sp. nov. 

actinoporella Giimbel in Alth 
A . podolica Alth 

ANTHRACOPORELLA Pia 

A. spectabilis Pia 
A . mercurii sp. nov. 
A . magnipora Endo 

ATRACTYLIOPSIS Pia 

A . darariensis sp. nov. 
belzungia Morellet 



Genus 

Genus 
Genus 
Genus 

Genus 

Genus 

Genus broeckella L. & J. Morellet 

B. belgica L. & J. Morellet 

Genus clypeina Michelin . 

C. jurassica Favre . 
C. inopinata Favre . 
C. lucasi Emberger . 
C. marteli Emberger 
C. parvula Carozzi . 
C. spp. (Cretaceous) 
C. merienda Elliott . 
C. sp. (Palaeocene) . 

?C. sp. (Permian) 

Genus cylindroporella Johnson 
C. barnesii Johnson 
C. arabica Elliott 
C. sugdeni Elliott . 
C. spp. . 



Page 
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CALCAREOUS ALGAE OF THE MIDDLE EAST 



Genus cymopolia Lamouroux . 
C. anadyomenea Elliott 
C. eochoristosporica sp. nov. 
C. tibetica Morellet . 
C. kurdistanensis Elliott . 
C. barberae sp. nov. . 
C. elongata (Defrance) Munier-Chalmas 

C. {Karreria) sp. 
Genus dactylopora Lamarck . 
Genus diplopora Schafhautl 
Genus dissocladella Pia. 

D. deserta sp. nov. . 
D. undulata (Raineri) Pia 
D. sp 

D. savitriae Pia 
Genus eogoniolina Endo 
Genus epimastopora Pia . 

" E. minima " (Tauridium sp.) 

E. sp. 
Genus furcoporella Pia . 

F. diplopora Pia 
Genus griphoporella Pia 

G. cf. peyforatissima Carozzi 
" G. arabica " (Ovulites maillolensis) Pfender 

Genus gyroporella Giimbel 
Genus indopolia Pia 

/. satyavanti Pia 
Genus larvaria Defrance 
Genus macroporella Pia . 
Genus morelletpora Varma 
Genus mizzia Schubert 

M . velebitana Schubert 
Genus munieria Deecke . 

M . baconica Deecke 
Genus neomeris Lamouroux 

N . cretacea Steinmann 
Genus pagodaporella Elliott 

P. wetzeli Elliott 
Genus palaeodasycladus Pia 

P. mediterraneus Pia 
Genus permoperplexella gen. 

P. atlenuata sp. nov. 
Genus pianella Radoicic" . 

P. gigantea (Carozzi) RadoiciC 

P. pygmaea (Giimbel) Radoicic" . 
Genus pseudoepimastopora Endo 

P. ampullacea sp. nov. 

P. cf. likana Kochansky & Herak 

P. iwaizakiensis Endo 



38 
39 
40 

41 
42 

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44 
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49 
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CALCAREOUS ALGAE OF THE MIDDLE EAST 



IV. 

V. 

VI. 

VII. 

VIII. 

IX. 



Genus pseudovermiporella Elliott 
P. sodalica Elliott . 
P. elliotti Erk & Bilgiitay 
Genus salpingoporella Pia 
5. annulata Carozzi 
5. apenninica Sartoni & Crescenti 
5. arabica sp. nov. . 
S. dinarica Radoicic" 
Genus terquemella Munier-Chalmas 
T. bellovacina Munier-Chalmas 
7". globularis Elliott. 
"T". sp. 
Genus teutloporella Pia 
Genus thaumatoporella Pia 
Genus thyrsoporella Giimbel 

T. silvestrii Pfender . 
Genus trinocladus Raineri 
T. tripolitanus Raineri 
T. perplexus Elliott 
T . radoicicae sp. nov. 
Genus triploporella Steinmann 
Stratigraphic Succession of Dasyclad Algae 
Geographical Distribution of Tethyan Algae 
Ecology ....... 

Evolution of the Dasycladaceae 
References ...... 

Appendix — Geographical Co-ordinates of Localities 
in Text ......... 



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70 

72 
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75 

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82 

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98 
101 

109 



SYNOPSIS 

The fossil flora of calcareous chlorophyte algae, family Dasycladaceae, from the Permian to 
Palaeocene succession of the Middle East, is described and figured. This material has been 
selected principally from extensive rock collections made by geologists of the Iraq Petroleum 
Group in Iraq, Qatar, Oman and Hadhramaut. Advantage has also been taken of much fossil 
comparative material from the remainder of the Middle East, the European and African circum- 
Mediterranean countries and elsewhere, and of herbarium specimens of Recent dasyclads from 
the warm seas of the Atlantic, Indian and Pacific Oceans. Dasyclad morphology, methods of 
study of fossil dasyclads, and the limitations of such material, are outlined, and the principles 
of classification employed are examined. The results are applied to the Middle East flora ; 
about 80 species, referred to 39 genera and 12 tribes of the family, are described and figured 
or discussed. Included are a small minority of fossils whose dasyclad nature is uncertain or 
which have been incorrectly described as dasyclads, and a few Dasycladaceae incerta sedis. 
Stratigraphically the general agreement of the Middle East dasyclad floras with those of Europe 
and elsewhere is confirmed, though differing local ranges for certain Upper Jurassic-Lower 
Cretaceous species are detailed. Geographically the homogeneity of the Tethyan dasyclad 
floras from west to east is confirmed at most stratigraphic levels ; the Middle East forms a 
central sector of this latitudinal belt. In the Palaeocene, evidence of the mixing of eastern 
and western elements in the Middle East area is noted. Ecologically the evidence of all the 
Middle East fossil dasyclads is in accord with what is known of their living descendants. 

Finally, from an evolutionary point of view, the most important points of detail are the 



6 CALCAREOUS ALGAE OF THE MIDDLE EAST 

interpretation of a Palaeocene genus as possibly having been similar to the atypical living 
Dasycladas in shedding gametes direct instead of by the usual dasyclad encystment, and in 
the conclusion that the terminal umbrella-type fertile discs seen in the living Acetabularia may 
be of different origin though of similar morphology in the fossil Clypeina. Also described is a 
species of Cymopolia showing the actual transition from cladospore to choristospore organization. 
The views of Julius Pia on the general course of dasyclad evolution are confirmed. No detailed 
explanation of this evolution can be offered, but the decline of dasyclads in abundance and 
importance throughout geological time, and their replacement by certain calcified Codiaceae 
in this respect, are now considered to be due to the differing relation of calcification to repro- 
ductive bodies in the two families, this itself probably due to their differing basic morphology. 

I. INTRODUCTION 

Present-day dasyclads are small single-cylindrical segmented or umbrella-shaped 
green algae, calcined in varying degree, and occurring mostly in warm very shallow 
waters in tropical and sub-tropical seas. The family is not a large one in number of 
component genera, and many of these illustrate markedly the phenomenon of dis- 
continuous distribution. Neomeris, for example, is largely divided in occurrence 
between the East and West Indies. When the fossil record is examined, the relict 
nature of the Recent survivors is seen at once. Ancestral forms range from the lower 
Palaeozoic onwards, and show a variety of strange genera now extinct. At some 
geological levels they occur in profusion over large areas, and are used as index 
fossils. Although individual sizes are small, when compared with those of some 
other marine algae, yet proportionally giant forms occur amongst the fossil dasyclads, 
and the Lower Carboniferous Koninckopora has been estimated to have attained a 
length of 50 cm. This phenomenon of former large size is also not uncommon with 
relict groups. 

In the largely arid land-area now known as the Middle East a thick succession of 
ancient sediments bears witness to the former occurrence there of the old Tethyan 
Sea. From Upper Palaeozoic to Mid-Tertiary times conditions of repeated shallow, 
warm-water, limy-bottomed shelf-areas afforded suitable environments for the 
growth of calcareous algae, and although, palaeontologically speaking, collections are 
rudimentary compared with those from Europe, yet examination of routine strati- 
graphical samplings has shown a succession of algal floras. In these the largest single 
group, taxonomically if not numerically, is the Dasycladaceae. Although they do 
not form whole reef-like rock-masses as do the Corallinaceae, nor occasion a mono- 
tonously distinctive rock-type as do the sand-like fragmentary remains of the 
Chaetangiaceae, yet the dasyclads impress themselves upon the mind of the student 
by the seemingly endless variety of structures, all based on a common plan. In their 
evolution, as interpreted by the Viennese worker Julius Pia over a working lifetime 
of thirty years, largely from European materials, there may be traced a progressive 
elaboration of their verticils or whorls of side-branches, the reproductive structures 
moving from within the stem-cell, first to within the side-branches, and then to 
specialised outgrowths adjacent to the subsidiary branches. But superimposed on 
this was a variability of calcification, as between one genus and another, and 
apparently showing no progressive trend throughout geological time. Some, 
heavily calcified, show hollow moulds of almost the whole set of branching structures 



CALCAREOUS ALGAE OF THE MIDDLE EAST 7 

in the plant and the fossil leaves no doubt, when well-preserved, of the state of 
evolution attained. Others calcify daintily and capriciously, each consistent for its 
genus, but anywhere between the stem-cell and near the tips of the finest outer 
branches. Both of these extremes are known ; and whilst distinctive enough both 
morphologically and stratigraphically, leave doubt as to what pattern of dasyclad 
alga formed them, and where it should be placed within the family. 

Middle Eastern Dasycladaceae were originally studied by me for their stratigraphic 
value, as explained below, and hence largely by comparison with those from else- 
where. In rock collections made for general survey purposes, rather than primarily 
for the amassing of good algal material, and showing frequently poor preservation, 
many occurrences have come to light which otherwise would have remained unknown, 
whilst on the other hand some of these specimens remain tantalisingly incomplete for 
palaeobotanical study. Nevertheless it may be said here that the Middle East 
mirrors and sometimes supplements the European record of dasyclad evolution from 
Permian to Eocene. Apart from very many points of detail, such as additional 
genera or species, extensions of generic range, and the filling in of geographical species- 
occurrences between East and West, there are several discoveries of especial interest, 
confirming earlier hypotheses or offering evidence for the probable ancestry of well- 
known genera. 

The present work originated as part of a study of the calcareous algae generally of 
the Middle East, undertaken as part of my duties for Iraq Petroleum Company Ltd. 
Commissioned early in 1953 by Dr. F. R. S. Henson, then in charge of the Company's 
geological research activities, it was undertaken as a section of a project for elucidat- 
ing the stratigraphical value for economic purposes of microfossil groups other than 
the foraminifera, and the results in this direction has been summarized elsewhere 
(Elliott, i960). Many tens of thousands of thin-sections, prepared from well and 
surface samples, have been examined, as well as large quantities of rock and sand 
samples. This material came primarily from Iraq, Qatar, Oman and the Hadhra- 
maut, where Iraq Petroleum and its associated companies operated, but much 
comparison material from the countries bordering the Mediterranean, and from the 
remainder of the Middle East, has been examined also, as well as Recent algae in the 
collections of the British Museum (Natural History) and elsewhere. Of those 
within the Company who have sent me dasyclad material for study, my thanks are 
offered to Messrs. H. V. Dunnington, E. Hart, D. M. Morton, K. al Naqib, A. J. 
Standring, W. Sugden, R. Wetzel, E. Williams-Mitchell, and Drs. R. C. van Bellen, 
Z. R. Beydoun, M. Chatton, and T. Harris. Of my many French friends and 
correspondents, I would single out for especial mention Professor J. Emberger, 
formerly of Algiers, who in exchanges has sent me many fine dasyclad rock-samples 
from the North African sector of the Tethys. At the British Museum (Natural 
History) members of the staffs of both Botanical and Palaeontological Departments 
have afforded me every facility, and I remember with gratitude the kindness and 
interest of the late W. N. Edwards, former Keeper of the latter department. Thanks 
are due to all those who have corresponded with me on dasyclad matters, from all 
over the world and too numerous to list here. Mr. R. C. Miller, when Senior Tech- 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



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nician at Iraq Petroleum's London headquarters, several times provided me with 
good transverse and longitudinal sections of dasyclads no larger than a few 
millimetres of fine pencil-lead, and Mr. J. Pope, of the Company's Photographic 
Department coped admirably with the problems of microphotography of largely 
monochromatic thin-sections : I thank them both. The distribution-maps and 
range-charts were prepared in Iraq Petroleum's Prodex Drawing-Office, and my 
thanks are due to Mr. E. G. Field and his staff for their services. 

At Reading University, where these studies were continued and the present work 
offered as a thesis for the degree of Ph.D., I am especially grateful to my supervisors, 
Professor P. Allen, Dept. of Geology, and Professor T. Harris, Dept. of Botany, for 



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CALCAREOUS ALGAE OF THE MIDDLE EAST g 

their help and encouragement, and their very real interest in the project. Also my 
thanks go to my fellow-students with whom I have had many interesting discussions, 
and to the staff of the Sedimentological Laboratory for services of all kinds. 

Finally, I would acknowledge my indebtedness to the Management of Iraq 
Petroleum Company, Ltd., who generously agreed to and made possible this liaison 
between academic and economic geology. Dr. C. Thiebaud, Exploration Manager, 
and Mr. H. V. Dunnington, Chief Geologist, who approved and submitted the project, 
I thank sincerely and gratefully for their efforts on my behalf. All the material in 
this paper has been presented to the British Museum (Natural History). 

II. STUDY AND CLASSIFICATION OF FOSSIL DASYCLAD ALGAE 

Modern views on the botanical classification of dasyclad algae, their relationship 
to other green algae and the precise systematic status to be accorded them, may be 
found in Fritsch (1935) and more recently in Egerod (1952) . Such work is necessarily 
based on the detailed study of structure, development and reproduction in the living 
plant. All the fossil forms described in this work are referred to a single family, the 
Dasycladaceae. Within this family the subclassification into tribes has been largely 
the work of palaeontologists, especially J. Pia, since the fossil forms are so numerous. 
Pia's classification appeared in the 1920s (Pia 1920 ; 1927) and was followed with 
slight modification and comment by later workers including Emberger (1944), 
Johnson (1954a ; 1961b) and Kamptner (1958). 

Whilst it cannot be over-emphasized that as a general rule the fullest understand- 
ing of fossils is only to be obtained from an understanding of their living descendants, 
where skeletal structures can be studied functioning with the associated organic 
tissues missing in the fossil, yet much depends on how much is preserved in the latter, 
and how well it is preserved. In Recent members of the red algal family Chaetan- 
giaceae, it was concluded by Svedelius (1953) that experimental spore-culture was 
necessary for conclusive pairing of the morphologically distinctive sexual and non- 
sexual generations. A morphological classification is thus inevitable with the fossil 
Chaetangiaceae, which in addition are notoriously fragmentary. For this general 
reason the account of dasyclad structure set out below stresses those structures and 
features of the plant which are of assistance in an understanding of the calcified 
remains found fossil. 

Individual living dasyclads are usually small, vertically-growing algae : one 
observer described them as resembling " little green sausages " (Church 1895). 
Attached at the base by a rhizoid or holdfast, the core of the plant is a proportionally 
long cylindrical stem-cell, extending from rhizoid to apex. From this, whorls or 
verticils of lateral branches are given off at successive closely-set levels : these 
branches may themselves divide more than once, and they also bear the sporangial 
bodies. Much of the plant above the rhizoid is crusted with calcium carbonate. 

The commonest fossils of dasyclads are thus small calcareous hollow cylinders with 
tubular pores and cavities in the thickness of the wall, the pattern of pores and 
cavities occurring again and again at successive levels in the wall-thickness along the 
cylinder. The main central tunnel represents the stem-cell, the branching tubular 



io CALCAREOUS ALGAE OF THE MIDDLE EAST 

pores the lateral branches and the cavities the sporangia. There may be a terminal 
" pepper pot " structure at the apex. Determination of the fossil is made on the 
detail, number, arrangement and size of these structures. The essential prepara- 
tions are a longitudinal cut or thin-section through the long central cylinder-axis, 
and a transverse section at right angles to this. More than one of the latter may be 
required when the lateral branches are strongly inclined relative to the horizontal 
plane. A whole, three-dimensional specimen, or at least a weathered surface to show 
surface-detail, is desirable for describing new material. A selection of such loose 
specimens for the preparation of orientated sections is ideal, but not always available. 
Once the essential structure is understood, the species may be recognized with 
practice in all manner of random oblique or tangential cuts. It should be noted that 
in exceptionally large dasyclads individual longitudinal and transverse sections, even 
if correctly orientated, may pass between verticil-detail and so not be diagnostic. 

Exact measurements of the dimensions of thallus, stem-cell, branch- and 
sporangial-detail are desirable in describing dasyclad algae. It should, however, be 
remembered that whilst species do show average size and proportions of both thallus 
and component structures, they are plants and, like all plant life, variable. Dimen- 
sions are therefore a guide and not an exact character in dasyclad taxonomy. 

A considerably greater variety of form has existed in dasyclads through geological 
time than survives at the present day. The notes which follow deal with the 
principal types which occur. 

The stem-cell may be thin- or thick-cylindrical, club-shaped with either gradual 
increase of diameter or bulbous termination or greatly swollen, even to a near- 
spherical shape. Normally it is represented in fossils by a simple central mould, but 
certain cylinders whose walls are formed by hollow spherical calcareous bodies, 
adjacent, touching or fused, e.g. Atradyliopsis, are interpreted as remains of dasy- 
clads in which the sporangia were within the stem-cell itself and calcified as a sub- 
dermal stem-cell peripheral zone to give the fossil seen. Occasionally there is some 
doubt as to whether a calcareous filling between these bodies occurred during the 
life-time of the plant, in the lower, older part, or is a post-mortem mineralisation 
feature (e.g. Aciculella) . 

Exceptional forms in which the stem-cell is creeping in habit, or modified into a 
thin support for a large terminal disc or discs, are dealt with separately below. 

The lateral branches have been described above as occurring at successive hori- 
zontal levels in whorls or verticils. Pia (1920) recognized a tripartite classification 
of their relationship to the stem-cell. In the more primitive aspondyl type the pores 
marking the origin of branches occur irregularly, more or less over the whole stem- 
cell surface. In the euspondyl type single branches are set in approximately 
horizontal whorls, whilst in the metaspondyl arrangement tufts of branches originate 
from the pores of the verticils. 

The lateral branches themselves may be single structures, or more commonly 
branched, so giving primaries, secondaries, tertiaries etc. The number of sub- 
branches at each point of branching or division is approximately constant within the 
species. These points of branching are constricted and there also occur genera in 



CALCAREOUS ALGAE OF THE MIDDLE EAST n 

which constriction of the individual branches and branchlets occurs without division 
at these constrictions e.g. Palaeodasycladus. 

The reproductive structures, usually termed sporangial cavities in the fossil 
literature, are often conspicuous features of the branch-detail, and are of great value 
in classification. They may be completely encased in the calcareous coating where 
this is well-developed, and indeed, in most similar living forms, gametes are only set 
free from resting cysts on the eventual post-mortem break-up of the calcareous 
structures. General classification of the condition seen in fossils is again tripartite 
and due to Pia. The endospore type is presumed to have had reproductive elements 
within the stem-cell. This is characteristic of the Palaeozoic and only such forms as 
the doubtful Atradyliopsis already mentioned and a species of Diplopora show any 
direct structural evidence of this condition. In the cladospore type, dominant 
throughout most of the Mesozoic, the reproductive cavities are considered to have 
been within swollen lateral branches. Finally, in the choristospore type the repro- 
ductive elements are located in special outgrowths, usually well-calcified, from the 
lateral branches. Commonly they are attached at the division of primaries into 
secondaries (e.g. Cymopolia) but various other positions characterise other genera. 
This type ranges from Cretaceous to Recent. Rezak (1959a) has drawn attention to 
the parallel between Pia's view of the migration of reproductive elements during 
phylogeny from stem-cell to lateral sporangia, and Egerod's summary (1952) of the 
migration during ontogeny of the dividing nucleus from the holdfast of the vegetative 
thallus into the gametangial rays of the reproductive thallus. Recent studies of the 
genetic mechanisms involved in this latter phenomenon in the living Acetabularia 
(Brachet 1965), do not invalidate this comparison. Summary of the chromosome 
mechanisms in the Dasycladaceae (Puiseux-Dao 1966) emphasizes their distinctive- 
ness amongst green algae. 

There exists a minority of dasyclads which depart from the usual pattern of a 
vertical calcareous cylinder described above. 

Vermiporella and the somewhat doubtful Psendovermiporella from the Palaeozoic 
are recumbent-irregular in form, indicating a presumed creeping thallus in life. 
The former branches, and the latter shows a peculiar double calcareous structure in 
part of the thallus. This is dealt with fully in the systematic descriptions below. 

In the Palaeozoic Mizzia and certain later genera the stem-cell occurred as con- 
secutive bead-like structures, almost always dissociated as found fossil. Certain 
Tertiary dasyclads (e.g. Larvaria) were of normal tubular pattern but the verticils 
came apart after death and usually occur fossil as separate ring-like structures. 

Another and commoner growth form is where the plant appears with a thin, 
lightly-calcified stem supporting a specialized flower-like disc or series of discs, 
usually found separate as fossils, in which the radial segments or " petals " are 
calcified structures containing the reproductive elements in life (e.g. Clypeina). In 
Acicularia these segments themselves came apart after death and occur as separate 
microfossils, of varying form, known as spicules. Not all such spicules, however, 
have this origin : some, such as the Tertiary Carpenterella, are believed to be 
dissociated structures from the interiors of dasyclads of modified cylindrical form. 



i.! CALCAREOUS ALGAE OF THE MIDDLE EAST 

Calcification 

During individual development recent dasyclads pass through several growth 
stages : calcification begins fairly late, often being initiated around the early repro- 
ductive structures, and thus it is the adult plant of which a fossil record is possible. 
Occasionally exceptional fossils, such as the Cretaceous Trinocladus, show differences 
in detail between the lower, earlier formed whorls and the upper, later ones, both 
being calcified. However, a combination of capriciousness in degree and occurrence 
of calcification for the members of the family viewed together, and constancy for the 
calcification of the individual species, is the rule in the Dasycladaceae. 

Consequently, the reconstructions possible of the plants which originated the 
calcareous fossils vary enormously. With heavy calcification a record is preserved 
of the stem, branch and sporangial details, and also the outline of the whole plant, 
only the finest branchlets projecting further during life. With those which calcify, 
but come apart after death, a fair degree of reconstruction is possible, and chance 
preservation of rare complete specimens illuminates the common segments or debris. 
Where calcification is confined to a narrow zone, either close to the stem-cell as in 
Pagodaporella, or between the tips of the branchlets only, as with Tersella, the 
details of the plant will probably always be doubtful. Finally, such odd remains as 
Aciculella, already mentioned, or tiny dissociated elements like Terquemella, render 
necessary the description of form-genera whose components may be of diverse origin 
and whose position within the family is unknown. 

List of Middle Eastern Fossil Dasycladaceae 

In the list below, those genera of dasycladaceae recognized in the course of the 
present work are set out under the appropriate " tribes ", or subdivisions of the 
family. These tribes, proposed by Pia (1920 ; 1927), have been followed and modi- 
fied by later workers, notably in the comprehensive schemes of Emberger (1944) and 
Kamptner (1958) while other workers, elements of whose classifications have been 
especially considered here, are Morellet (1922), Johnson (1954a ; 1961b) and Rezak 

(1959a). 

Classification of this kind is based on structure as preserved in the fossils, and on 
phylogeny, which may be regarded in this connection as interpreted structure. The 
student of phylogeny assigns values to elements of structure in accordance with his 
or her experience of the group studied. Close similarities and near-identity, 
particularly of external form and gross structure, are often discounted in favour of 
smaller and less obvious features. These latter are valued on account of their 
persistence throughout time or their alleged significance as early or late manifesta- 
tions of distinctive structures in related members of the group. In general, this 
interpreted structure determines the taxonomic category allotted. However, the 
success of a group, evidenced by numerical abundance of individuals and extensive 
minor variation from a common structure, as opposed to rare, but profound deviation 
which were evidently biologically unsuccessful or unfortunate, often leads to a 
taxonomic up-grading of the group being classified. 

Such classification, with its very different allocation of importance to the same or 



CALCAREOUS ALGAE OF THE MIDDLE EAST 13 

similar structures in related groups, reflects attempts towards a real understanding 
of evolution, and dissatisfaction with rigid morphological classification, however 
logically contrived. The subjective elements in such reasoning, normally sub- 
ordinate, become much more apparent when subdivision is attempted of a relatively 
homogeneous biological group. In the " small change " of evolution personal 
choice in detailed classification becomes obvious. Thus Clypeina has been referred 
both to the Diploporeae (Pia 1927, Emberger 1944) and to the Acetabulareae 
(Morellet 1913 ; 1922 ; 1939 ; Rezak 1957). Since clypeiniform remains are now 
recorded Irom the Permian (p. 36) it seems possible that the different morphological 
trends seen in dasyclads may have evolved more than once, and the classification of 
such similar forms is difficult. In the present work Clypeina is placed in the new 
tribe Clypeineae : the reasons for this and the relationship of the genus to Adino- 
porella, here left in the Diploporea, are discussed below (p. 99). 

In the Dasycladaceae considered here, the increasing complexity of branch- 
structure, and transference of position of reproductive structures already mentioned, 
are noticeable evolutionary trends. It is inevitable, however, that in classifying 
fossil genera represented by very varied results of superimposition of localized 
calcification on different stages of these trends, that frequently some uncertainty 
should be felt as to the appropriate tribe. The Middle Eastern genera and species 
described below have been so referred in accordance with literature quoted. For 
many genera, simple or complex, e.g. Diplopora or Neomeris, there is no uncertainty. 
For others, e.g. Atractyliopsis or Griphoporella, the nature of the fossil ensures its 
relegation as incerta sedis. Between these extremes are several doubtful cases, 
assigned here to a tribe for consistency, in accordance with published accounts ; 
e.g. Cylindroporella to Diploporeae (Kamptner 1959) and Terquemella to Dactylo- 
poreae (Morellet 1922 ; Emberger 1944). Pagodaporella is assigned to Dasycladeae, 
in view of its analogy with Dasycladus. Mizzia is placed under Diploporeae follow- 
ing Rezak (1959b), and Acroporella also, in view of its author's opinion on its relation 
to Salpingoporella (Praturlon 1964). The writer is in agreement with the need for 
subdivision of the Diploporeae expressed by Rezak (1959a : 125), but has not 
attempted this, still less general reclassification of dasyclad tribes, in the present 
study of Middle East representatives of the family. The recent discovery of a 
Dissocladella in the older Mesozoic (Ott 1965), and the phylogenetic considerations 
given by this writer, show how random and incomplete is the evidence for major 
re-classification. 

The table given, therefore, represents current conventional taxonomic assignment 
of the genera listed, which are dealt with alphabetically in the main descriptive part 
of the work, where the synonymies are selected to cover primary descriptions, 
revisions and Middle East occurrences only. 

Family DASYCLADACEAE Kutzing 1843 
orth. mut. Hauck 1884 

Tribe DASYPORELLEAE Pia 1920 
A nthracoporella 



M CALCAREOUS ALGAE OF THE MIDDLE EAST 

Tribe CYCLOCRINEAE Pia 1920 
Epimastopora 

P sen do epimastopora 

Tribe DIPLOPOREAE Pia 1920 
Acroporella 
Actinoporella 
Cylindroporella 
Diphpora 
Gyroporella 
Macroporella 
Mizzia 
Munieria 
Permoperplexella 
Pianella 
Salpingoporella 

Tribe TEUTLOPORELLEAE Pia 1920 
Teutloporella 

Tribe TRIPLOPORELLEAE Pia 1927 
Triploporella 
Broeckella 

Tribe THYRSOPORELLEAE Pia 1927 
Belzungia 
Dissocladella 
Thyrsoporella 
Trinocladus 

Tribe CONIPOREAE Pia 1920 
Palaeodasycladus 

Tribe CLYPEINEAE (trib. nov. ; see p. 99) 
Clypeina 

Tribe DACTYLOPOREAE Pia 1927 
Terquemella 

Tribe DASYCLADEAE Pia 1920 
Pagodaporella 

Tribe NEOMEREAE Pia 1920 

Cymopolia 

Indopolia 

Karreria 

Larvaria 

Neomeris 

Tribe ACETABULARIEAE Pia 1920 
A cicularia 



CALCAREOUS ALGAE OF THE MIDDLE EAST 15 

DASYCLADACEAE incerta sedis 
Atractylopsis 
Furcoporella 
Griphoporella 

Problematica, possibly dasycladaceae 

Pseudovermiporella (PDASYPORELLEAE) 

Hensonella (PDIPLOPOREAE, as Salpingoporella dinarica) 

Algae, not dasycladaceae 
Thaumatoporella 

" Epimastopora minima Elliott " (= Tauridium sp.) 
" Griphoporella arabica Pfender " 
(= Ovulites maillolensis Massieux). 

III. SYSTEMATIC DESCRIPTIONS 

In the descriptions which follow, the geological ages of all material mentioned are 
given in terms of local rock-units and standard international stages as far as possible. 
Every effort has been made to take account of all relevant literature up to the end 
of 1966. A bibliography of the geology of the Middle East is far outside the scope 
of the present work, but key publications may be quoted for Iraq, Qatar, Oman and 
the Hadhramaut from which the vast majority of the specimens were collected. 
For Iraq, the very detailed Lexique Stratigraphique International, listed in the 
present bibliography both under Bellen, R. C. van (1959), and under Dunnington, 
Wetzel & Morton (1959), is invaluable. The Hadhramaut material is similarly 
covered by Beydoun (1964). A suitable account for the much smaller and simpler 
Qatar is that by Qatar Petroleum Company, Ltd. (i960). Oman is covered by the 
general account of Morton (1959), and the detailed local papers of Hudson and 
collaborators are mentioned where relevant in the present study. 

The regional location of the numerous small localities quoted are best gleaned from 
these works ; in the present text they are given with the appropriate province or 
administrative division. The geographical co-ordinates of these localities are 
listed on p. 109. 

Genus ACICULARIA (d'Archiac) Munier-Chalmas 

Diagnosis. Calcareous spicules, typically elongate-cuneiform, circular or 
flattened in cross-section, set peripherally with small spherical cavities ; in life part 
of the fertile whorl of the plant. 

Acicularia was proposed by d'Archiac (1843 : 386) for certain fossil spicules 
occurring in the Paris Basin Eocene. Referred to different animal groups by various 
authors, their algal origin was recognized by Munier-Chalmas (1877), and the sub- 
sequent discovery of a living species confirmed this diagnosis. Munier-Chalmas 
published little but the bare statements of this and other original discoveries, and 
the details of his species, and the subgenus Briardina, are to be found in later authors, 
notably in the classic works of L. and J. Morellet (1913, 1922), and in the paper by 



16 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Costantin (1920) which gives some of Munier-Chalmas' original figures. The recent 
.[aciduria has been merged as a section Acicularioides of Acetabularia (Egerod 1952), 
but in the fossil state at least the remains are distinctive and the name a useful one. 

Acicularian spicules are typically small elongate needle-like calcareous bodies, 
derived from the specialized fertile disc of the plant and containing tiny spherical 
sporangial cavities. (Somewhat similar discoidal or spherical bodies, Terquemella 
of Munier-Chalmas were recognized by the Morellets as sporangial structures from the 
walls of fossil Bornetelleae (= Dactyloporeae), which are of normal tubular dasyclad 
pattern and not umbrella-shaped like Acicidaria or Acetabularia) . Both morpho- 
logical types of spicule are known from the Jurassic onwards. Whilst the attribution 
of the Tertiary species is as given above, the origin of the Mesozoic forms is much 
more doubtful. Pia (1936a, b) has described Cretaceous spicules which he referred 
to Acicularia but considered might indicate a connection between Acicularia and 
Terquemella, obviously using the latter in a strictly morphological sense. 

In the Middle East true Terquemella spp. occur in the Palaeocene-Lower Eocene ; 
these species are dealt with below under Terquemella. The remaining Acicularia 
spp. are now described here. 

Acicularia antiqua Pia 

(PI. 1, figs. 1, 3) 

1936a Acicularis antiqua Pia : pi. 3, figs. 1-14. 
1955b A. cf. antiqua Pia ; Elliott : 126. 

Description. Rounded, cuneiform, calcareous bodies, circular or ovoid in cross- 
section, containing numerous submarginal spherical hollows (sporangial cavities). 
Length up to 0780 mm., with maximum diameter of 0-364 mm. The sporangial 
cavities are consistently about 0-040 mm. in diameter, and in thin-section appear 
set apart by their own diameter or a little more along the margins of the spicules. 

Horizon. Cretaceous of North Africa and the Middle East. 

Material. Seen in thin-section from the subsurface Garagu formation (Valan- 
ginian) of Kirkuk well No. K 116 (Kirkuk Liwa, Iraq), from the Sarmord and 
Qamchuqa formations (Neocomian and Aptian-Albian) of the Surdash district 
(Sulemania Liwa, Iraq), from the Upper Musandam formation (Lower Cretaceous, 
Barremian-Aptian) of the Hagab area, Oman, Arabia, and from the Maestrichtian 
of Diza, (Erbil Liwa, Iraq). 

Remarks. Random sections of acicularian spicules are not uncommon at many 
levels in the Middle East Cretaceous. With few exceptions, they may be divided 
into two classes, on the size of the sporangial cavities. The smaller, always set in a 
circular section indicating a spherical spicule, is described elsewhere under Terque- 
mella s.l. The larger, described above, occurs in a variety of random cuts suggesting 
a rounded-cuneiform spicule. For this form Pia's Acicularia antiqua (Pia, 1936a) 
appears to be available. The type material, from the Cenomanian of Libya, 
Northern Africa, is described as probably wedge-shaped or pointed, length probably 
not exceeding twice the thickness, greatest diameter 0-330 mm., diameter of spore- 



CALCAREOUS ALGAE OF THE MIDDLE EAST 17 

cavities 0-040-0-055 mm., and not curved or hooked as in A. dyumatsenae Pia from 
the Indian Danian (Pia 1936b). The Middle Eastern material, on the basis of the 
few available dimensions and characters, seems to vary little beyond this, and the 
name is adopted. A few examples from the subsurface Garagu of Kirkuk show 
exceptional sporangial diameters of 0-065 mm., but they occur in random transverse 
cuts only. A. endoi Praturlon (1964), from the Italian lower Cretaceous, is 
described as a spicule, slightly larger with larger sporangial cavities, which however 
are more regularly and peripherally arranged to give a starred appearance in thin- 
section. 

A . antiqua is more common in Lower than Upper Cretaceous in my experience, but 
ranges from bottom to top of the system. If the spicules are the remains of more 
than one botanical species in this long period, there is no apparent evidence of this in 
the microfossils as preserved. They should not be confused with the micro- 
problematicum Coptocampylodon (Elliott 1963a) which resembles an acicularian in 
transverse cut, but is readily distinguishable by the longitudinal sections normally 
associated. 

1 Acicularia elongata Carozzi 

1947 Acicularia elongata : Carozzi : 13, figs. 1-8. 

Remarks. Carozzi's species, from the Swiss Upper Jurassic, is a distinctively 
elongate spicule of rather ragged outline. In the Upper Jurassic of Jabal Kaur, 
Oman, Arabia, remains occur which are possibly of the Swiss species, but are not 
well enough preserved to permit of a positive reference. They are associated with 
Pianella gigantea Carozzi and the microcoprolite Favreina salevensis (Parejas), also 
described from the Swiss Upper Jurassic. 

Acicularia (Briardina) sp. 

(PI. 1, fig. 6) 

1913 Acicularia section Briardina Munier-Chalmas ; L. & J. Morellet : 33. 

Remarks. In the Palaeocene Limestones of the Batinah Coast, Oman, one or 
two examples of a small acicularian apparently referable to this section or subgenus 
have been noted. The best shows in longitudinal thin-section as a needle or narrow 
wedge-shaped spicule, 1 mm. long, 0-22 mm. wide at the outer end and slightly 
hooked at the inner (pointed) end : the sporangia are 0-078 mm. in diameter, in a 
double row, narrowing to a single on the upper face. The section cuts at the thinner 
end through the sporangia of the lower face, the elongate spicules of species of 
Briardina being thin, with flat or slightly concave upper and lower surfaces. 

This may be the earliest representative of the subgenus, the Paris Basin species 
being Lutetian or later in age (Morellet 1913, 1922), and the acicularians from the 
Montian (Morellet 1940) not being referred to the subgenus. 

Genus ACROPORELLA Praturlon 1964 
Diagnosis (after Praturlon). " Not segmented DASYCLADACEAE having 



i8 CALCAREOUS ALGAE OF THE MIDDLE EAST 

simple, long, not ramified, akrophorous branches. Reproduction probably endo- 
spore ". ' The branches are namely by no means ' gegen aussen deutlich erweitert ', 
as in Salpingoporella, Pianella, Macroporella, as well as do not incline to shut out- 
wards as in Oligoporella. They are namely intermediate between the two types ". 
(Praturlon 1964 : 177). 

Acroporella assurbanipali sp. nov. 
(PI- 1. %• 5) 

i960 Macroporella sp. ; Elliott : 222. 

Description. Cylindrical tubular calcified dasyclad, external diameter 1-36 mm., 
internal diameter 0-55 mm. (40% of external) ; successive near-horizontal verticils, 
probably 3 or 4 per mm. of tube-length, of perhaps twelve radial branches each. The 
single branches communicate with the stem-cell cavity by a pore of about 0-052 mm. 
diameter : they then swell out to a fig- or flask-shaped cavity of 0-182 mm. maximum 
diameter, narrow to a slightly curved tube of 0-078 mm. diameter, and at the outer 
surface flare out to a shallow terminal diameter of 0-156 mm. 

Horizon. Subsurface Lower Cretaceous of Iraq. 

Holotype. The specimen figured in pi. 1, fig. 5 from the subsurface Garagu 
Formation (Valanginian-Hauterivian) of Kirkuk Well no. 116, Iraq. V. 52032. 

Remarks. Acroporella Praturlon (type-species A. radoicici Praturlon 1964) is a 
primitive form from the Lower Cretaceous of Italy, apparently of somewhat inter- 
mediate branch-characters, though well figured and described by him. The Kirkuk 
specimen exactly fits his general diagnosis for branch -structure, rather better than 
the type-species, in fact, but the thallus shows more than double the dimensions of 
the Italian species, and the shape of the peculiar branches is unique. It is therefore 
made the type of a new species. The exact orientation of the curved branches 
relative to the cylinder-axis is difficult to make out from the long tangential section : 
the swollen portions may have housed the sporangia in life. 

The specific name commemorates a king of ancient Assyria, within whose former 
boundaries Kirkuk now lies. 

Genus ACTINOPORELLA Gumbel in Alth 

Diagnosis. Verticils of several straight radial calcareous tubes, approximately 
in the same horizontal plane, separate for most of their length but meeting centrally 
in a calcareous ring, each hollow tube communicating by a single pore with the 
central cavity. 

Actinoporella was created by Gumbel (Alth 1882), with type species Gyroporella 
podolica Alth (1878), which came from the Portlandian of Podolia (Cushman & 
Glazewski (1949) ; then in Austria, but subsequently in Poland and now included 
in the U.S.S.R.). This alga, represented by little impressions and hollow moulds of 
the verticils, was studied and reconstructed by Pia (1920 ; 1927) loose solid 
specimens from the same area have been seen by me. Each verticil shows numerous 



CALCAREOUS ALGAE OF THE MIDDLE EAST 19 

radial tubes, slightly curved but approximately horizontal, about 20 in number, 
which are interpreted as the calcareous coatings or casings of simple primary side- 
branches. These are free for much of their length, but touch and become fused 
centrally, to form a circular ring through which the stem-cell passed. Pores on the 
inner surface of the ring mark the old communications of side-branches with stem- 
cell. A succession of such verticils built up in life the peculiar plant shown in Pia's 
reconstruction (fig. 2). 

Subsequently Carozzi (1948) figured numerous thin-sections determined as 
Adinoporella podolica, from the Swiss Portlandian-Purbeckian. It is with these 
sections that the Middle Eastern material has been correlated, no solid individuals 
having been extracted. The commonest thin-section appearance is given by 
tangential cuts through the finger-like projections or side-branches, which show as 
chains of separate or touching circles. Less commonly vertical sections along the 
main axis show the central stem-cell and paired opposite side-branches, and rarely, 
transverse cuts show a whole disc or verticil. 

Although locally common in the European Portlandian, and recorded from as low 
as Sequanian (Francois, Lehmann & Maync, 1958), this alga is characteristic in the 
Middle East of the Lower Cretaceous and has never been seen there in the Jurassic. 
In Italy (Sartoni & Crescenti 1962) it is recorded from both Tithonian and Valan- 
ginian-Hauterivian. It appears to be slightly more common in the Middle East at a 
Valanginian-Hauterivian level than in the Barremian-Aptian above (Elliott 1955b), 
but forms a noticeable constituent of the Middle Eastern " debris-facies " (Elliott 
1958a), an off-shore accumulation of fine calcareous algal fragments in fire-grained 
sediments. 

The relationship of Adinoporella to Clypnna, and their positions within the family 
Dasycladaceae, are discussed elsewhere (p. 99). 



Adinoporella podolica Alth 
(PI. 1, figs. 2, 4, 7) 

1878 Gyroporella podolica : Alth : 83, pi. 6, f. 1-8. 

1882 A ctinoporella podolica Alth : 322. 

1920 A. podolica Alth ; Pia : 95, fig. 19, pi. 7, f. 1-7. 

1948 A. podolica Alth ; Carozzi : 353, f. 49. 

1955b A. podolica Alth ; Elliott : 126, pi. 1, f. 1. 

1958a A. podolica Alth ; Elliott : 255, pi. 45, f. 1. pi. 47, f. 5. 

i960 A. podolica Alth ; Elliott : 222, 223. 

Description. Verticils of from i-o to i-6 mm. or more total diameter, each con- 
sisting of a central calcareous ring with inner diameter of about 21% of the total 
diameter ; from this ring project 13 to 20 largely separate tubular elongate thin- 
walled cylindrical rays, outwardly directed and all very gently curved upwards on 
the same side of the horizontal plane. Near and at the ring the walls of the rays are 
fused, to give a thickened calcareous structure, and the hollow interiors of the rays 
communicate each by a single pore with the main central cavity. 



20 C VLCAREOUS ALGAE OF THE MIDDLE EAST 

Horizon. Upper Jurassic and bottom Cretaceous of Europe : Lower Cretaceous 
of the Middle East. 

Material. Numerous random thin-sections. In Iraq seen in the Sarmord 
Formation (Valanginian-Hauterivian) of Jebel Gara, Mosul Liwa, and Surdash, 
Sulemania Liwa ; from the Garagu Formation (Valanginian) of Kirkuk well no. 116 
(subsurface), of Banik (Mosul Liwa) and of Fallujah Well (subsurface : Dulaim 
Liwa), from the Qamchuqa Formation (Barremian-Aptian) of Kirkuk well no. 116 
(subsurface) and from Zibar-Isumeran (Mosul Liwa). In the Hadhramaut (Southern 
Arabia), seen in Barremian-Aptian Orbitolina-limestone from Mintaq, Wady Hajar, 
and from the Aptian of Ghabar. 




Fig. 2. Reconstruction (after Pia 1920) of A ctinoporella podolica Alth. From top to bottom 
(1) vertical section (2) decalcified portion with anterior branches removed (3) decalcified 
portion with all branches in position (4) branches with calcareous coating in position (5) 
calcareous skeleton alone. X40 approx. 



Remarks. This species, mostly Upper Jurassic in Europe, appears to be Lower 
Cretaceous in its Middle East occurrences. Pia, dealing with the Podolian type 
material, relegated A. gumbeli to the synonymy of A. podolica, regarding the 
differences as not significant. Carozzi referred his Swiss material to A. podolica 
likewise. This practice is now followed with the Middle East material. This latter 
suggests smaller verticils and possibly a lower average number of rays than in the 



CALCAREOUS ALGAE OF THE MIDDLE EAST 21 

European fossils, but good series of solid verticils free from matrix would be needed 
to evaluate this decisively. Nothing like the distinctive A. sulcata Alth (Pia 
1920 : 100, fig. 20) has been seen. 

Actinoporella podolica is highly distinctive in random thin-section. Its thin- 
walled but coherent fragments cannot easily be confused with any species of Clypeina, 
whose verticils are more massive, except perhaps the Valanginian C. marteli 
Emberger, which has only about half the number of rays or branches per verticil. 
Munieria, apparently more solid, is much more fragmentary, and shows as smaller, 
more problematic debris : possibly its calcium carbonate was initially more fragile. 

Genus ANTHRACOPORELLA Pia 

Diagnosis. Calcified unsegmented branched cylindrical dasyclad with close-set, 
aspondyl dichotomous side-branches. 

Anthracoporella, described by Pia (1920), is a primitive dasyclad from the late 
Palaeozoic. The tubular thallus is exceptional in branching, often at a wide angle. 
The stem-cell is proportionally large in diameter to the surrounding wall-thickness in 
which the aspondyl dichotomous side-branches are very numerous, fine and closely 
set. The calcification may not have reached quite to the stem-cell, and the lateral 
branches probably projected considerably beyond the calcified zone. 

In a later paper Pia (1937) listed occurrences of the type-species A. spectabilis, 
initially described from the Upper Carboniferous of the Austrian Southern Alps. 
Species of the genus are characteristic of the Upper Carboniferous and Permian of 
Alpine Europe and Asia, and occur also in the southwestern United States and in 
Madagascar. 

In the revision of the Middle Eastern material for this study two species are 
recognized, the distinction being based mostly on size. A . spectabilis Pia is much the 
larger, with outer tube-diameters commonly up to 5 mm. or more (5-8 mm. quoted 
by Pia as a maximum ; Bebout and Coogan (1964) record up to 8-9 mm.). Smaller 
individuals or branches of this species, associated with the larger, may measure as 
little in diameter as 1-5 mm., but are exceptional. The second species, now described 
as new, is represented by solitary occurrences of tubes of diameter of less than 1 mm. 
This was at first considered a dwarfed variety and later in time than the large type- 
species, but their ranges overlap, and they seem distinct. 

Anthracoporella spectabilis Pia 

(PI. 2, figs. 1, 2) 

1920 Anthracoporella spectabilis Pia : 15, fig. 3, pi. 1, figs. 7— II. 
1937 A. spectabilis Pia ; Pia : 795, 809, 822. 
i960 A. spectabilis Pia ; Elliott : 219. 

Description. Thallus of branched tubular dasyclad pattern, up to 5-6 mm. or 
more in external diameter, stem-cell cavity large, d/D ratio 50-80%, the larger 
examples being progressively thinner- walled. Side-branches simple, about 0-040 
mm. diameter, sometimes dichotomous, aspondyl in arrangement, crowded and very 



22 CALCAREOUS ALGAE OF THE MIDDLE EAST 

numerous, more or less at right angles to main axis and giving a characteristic dot and 
dash appearance in slightly oblique transverse cuts. About 20 of these radial pores 
seen in 1 mm. of wall in a large example, and a small example of 1 mm. diameter 
showed a total of about 60 (both in transverse section). 

Horizon. Both Middle East occurrences of this species are in derived material, 
at Jebel Busyah and Jebel Hagab, Oman, Arabia. The former occurrence is in 
cobbles of derived limestone in a presumed Triassic conglomerate : associated with 
Anthracoporella are the algae Tubiphytes and Pseudoepimastopora, and the limestone 
of a similar cobble was dated by Dr. M. Chatton as Middle Permian on the evidence 
of Parafusulina shiptoni and other foraminifera, the fusulinid being compared with 
that from post-Artinskian Permian somewhat younger than the zone of P. kattaensis 
of the Salt Range (M. Permian of India). The Jebel Hagab occurrence is in derived 
material associated with the Mesozoic Musandam Limestone. Tubiphytes occurs 
with A. spectabilis, somewhat recrystallized, and this appears to be derived Permian 
material too. 

Material. See under Horizon. 

Remarks. Pia's Austrian type material was from the Upper Carboniferous- 
Lower Permian level ; Maslov (1956) records it from the Upper Carboniferous of the 
Urals, U.S.S.R. Bebout & Coogan (1964) record a large and proportionally very 
thin-walled form of the species from the subsurface early Permian (Wolfcampian) of 
Texas. Other records are discussed below under A. mercurii sp. nov. 

Anthracoporella mercurii sp. nov. 

(PI. 1, fig. 8) 

Description. Similar in form, growth and branches to A . spectabilis, but much 

smaller, diameter 0-5-0-9 mm. ; (relatively thicker-walled, d/D 40-60% ; pores 

radial (branches of 0-026 mm. diameter) ; a transverse section of one individual 

showed about 40 such branches). 

Horizon. Permian of the Middle East and Tunisia (see below). 

Holotype. The specimen figured in PI. 1, fig. 8 from the Permian, Bih Dolomite, 
of Wady Bih, Jebel Qamar, Oman. V. 52035. This limestone is dated in fusulinid 
evidence by Dr. Chatton as belonging to the " Neoschwagerina-Verbeekina zone of 
low Guadalupian age (Wordian) ". 

Other Material. Random sections from the lower Permian of Ora and Harur, 
Mosul Liwa, N. Iraq (Zinnar Limestone (Artinskian) of Hudson, 1958) ; from the 
Permian of Jebel Qamar, Jebel Hagab, and Tawi Silaim, all Oman ; in derived 
Permian material in the Upper Cretaceous Hawasina formation of Juweiza Well, 
Trucial Oman ; and in derived Permian material associated with the Mesozoic 
Musandam Limestone at Jebel Hagab, Oman. 

Remarks. A. mercurii, while much smaller than A. spectabilis is distinctly larger 
than the tiny (Upper Carboniferous) A. kasachiensis (Maslov 1956), and differs 
noticeably in proportions of the component structures. It differs in its occasionally 



CALCAREOUS ALGAE OF THE MIDDLE EAST 23 

divided branch-structure from the Japanese Lower Carboniferous Anatolipora 
(Konishi 1956), and similarly from the English Lower Carboniferous Nanopora 
anglica (Wood 1964) ; Wood refers Anthracoporella fragilissima to this latter genus 
also. Johnson's U.S.A. records of Anthracoporella from the Permian of New Mexico 
and Upper Permian of Texas (Johnson 1942 ; 1951) may well be of A. mercurii. 
Outside the Middle East, it occurs in the Upper Permian of Tebaga Well, S. Tunisia. 
The species appears to be more wide-spread in scattered occurrences than the large 
localized A. spectabilis, and is dedicated to the god Mercury who presided over travel. 

Anthracoporella magnipora Endo 

1951 Anthracoporella magnipora Endo : 124, pi. 10, figs. 4, 5. 
1963 A. magnipora Endo ; Fliigel : 85, pi. 1, fig. 1. 

This species, originally described from the Japanese Permian, is known to me in the 
Middle East only from Flugel's record quoted above : Permian of the Ala Dag, 
Taurus Mountains, Southern Turkey. 

Genus ATRACTYLIOPSIS Pia 1937 

Diagnosis. Fusiform, cylindrical or ovoid tubes formed of adjacent touching or 
fused hollow calcified spheres. 

Atractyliopsis was proposed by Pia (1937) for certain Upper Palaeozoic algal 
micro fossils which consist essentially of groups of adjacent, touching or fused hollow 
calcified spheres, occurring in the form of fusiform, cylindrical or bead-like bodies. 
These were regarded by him as somewhat similar to his earlier genera from the 
Triassic, Aciculella and Holosporella (Pia 1930). These he had interpreted as the 
remains of dasyclads in which the only calcified structures were the walls of endo- 
sporic sporangia set subperipherally within the main stem-cell, and he compared 
these with the Triassic Diplopora phanerospora in which these structures are seen 
within a normal calcified diplopore wall-structure. Holosporella is a hollow tube ; 
Aciculella a solid shaft, regarded as calcified internally during the lifetime of the alga. 

Pia gave three figures of Atractyliopsis, two Carboniferous, one Permian, without 
assigning a type-species or species-names ; he considered these fossils as fusiform 
segments. The Permian form was later named A. lastensis (Accordi 1955), fully 
described from Italian topotype material, and recognized as cylindrical in form. 
Meanwhile Wood (1940) described the similar Coelosporella from the English Car- 
boniferous, and mentioned its cylindrical form as differing from the alleged fusiform 
Atractyliopsis. Coelosporella however shows a much more solid wall than the other 
forms, and ovoid outwardly-directed sporangia, and may be regarded as valid on 
these grounds. Atractyliopsis, which differs only in larger dimensions and geological 
age from the earlier-described Holosporella, is retained here, since such fossils could 
originate from dasyclads of very different pattern. 

In the Middle East only one species of Atractyliopsis is known : this occurs in a 
somewhat similar facies and at the same level as the type-species, but less abundantly. 



24 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Atractyliopsis darariensis sp. nov. 
(PI. 2, figs. 3, 4, 5) 
i960 A. lastensis Accordi ; Elliott : 219. 

Description. Hollow cylindrical tubular structures, straight or gently curved, of 
up to 5-0 mm. observed length, 073 maximum external diameter : walls formed of a 
single layer of adjacent, touching or fused hollow spheres of 0-13 mm. internal 
diameter, original wall-thickness of spheres variable but 0-010-0-020 mm. in detached 
spheres. Primary calcification variable : the spheres may be more or less set in 
calcite formed by their fused walls, or almost isolated, with the outer surface of the 
cylinder truncating their outer curves, sometimes completely, to leave external 
openings, and their inner curves projecting roundly and unabraded into the cylinder- 
cavity. 

Horizon. Upper Permian of Northern Iraq. 

Holotype. The specimen figured in PI. 2, fig. 5, from the Upper Permian Darari 
or Upper Chia Zairi Formation, Ora, Mosul Liwa, North Iraq ; V. 52037. 

Paratypes. The specimens figured in PL 2, figs. 3, 4, same horizon and locality 
as the holotype ; V. 52015, 52037. 

Other Material. Fragments in random thin-sections, same horizon and 
locality. 

Remarks. This is very closely related to the type-species A. lastensis Accordi 
from the Upper Permian Dolomites of Northern Italy (Accordi 1956). Both occur 
with a similar Gytnnocodiuni-floTa. in a rather similar facies at the same level. A. 
darariensis is described here as distinct since the cylindrical remains seem to have 
been markedly longer than in the Italian species, but the two are probably con- 
temporary geographical species at most. Much depends on secondary calcification, 
which has to be distinguished very carefully where possible from that of the original 
sporangial coatings, and the Italian and Iraqi specimens are differently preserved in 
this respect. The measurements given above under " Description " are carefully 
taken from specimens without secondary calcification, or with it easily distinguish- 
able as such when present. In the Italian topotype material available to me 
Atractyliopsis lastensis is much more abundant than in the Iraqi material, where A. 
darariensis is a minority-constituent in a flora of Gymnocodium and Permocalculus. 

The Iraqi species is distinct from the Austrian A. carnica E. Fliigel. Although 
described in great detail (E. Fliigel 1966), the abundant material figured and 
described by this writer shows only circular and oval cross-sections. 

Praturlon (1963a : 132) has figured a thin section which shows Atractyliopsis set 
vertically (axially) within Permocalculus cf . forcepinus (Johnson) , (Chaetangiaceae or 
perhaps Codiaceae). He makes the interesting suggestion that this is the asexual 
form of the species, which is associated with other specimens of Permocalculus show- 
ing normal " sporangia " (Pcystocarps) and regarded as the sexual form. That is, 
the Atractyliopsis is to be regarded as part of the internal structure of the Permo- 
calculus, and is therefore not a dasyclad, nor indeed, a separate alga at all. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 25 

In the Iraqi material Atractyliopsis is associated with very abundant Permocalculus, 
but is itself rare. It is confined to the Darari Formation or top division of the Iraqi 
Permian, whereas Permocalculus ranges through the whole Chia Zairi, representing 
most of the system. It has never been seen inside Permocalculus in this material in 
the present study. The occasional occurrence of smaller fossils within larger ones by 
normal disturbance of randomly associated material on the sea-floor is not uncommon 
(cf. the perfect fit of the Palaeocene codiacid Ovulites within the dasyclad Trino- 
cladus ; PI. 23, fig. 2). With this in mind, I prefer to retain the older view of Pia 
(1937), that Atractyliopsis represents a zone of calcified sporangial structures set 
marginally in the dasyclad stem-cell. There is no direct proof of this for Atractyli- 
opsis itself, but a comparable structure exists in Diplopora phanerospora Pia (Pia 
1926), where both internal and external structures are calcified and the morphology 
is such that accidental post-mortem fitting is impossible. 

Genus BELZUNGIA Morellet 1908 

Diagnosis. Hollow ovoid or elongate bead-like calcareous units, open at both 
ends : the thick wall perforated by verticils of radial dichotomising and swollen 
canals, which terminate externally as a pattern of small pores. 

Belzungia (Morellet 1908) bears the same relation to Thyrsoporella as Cymopolia 
does to normal tubular dasyclads : that is, it possesses similar verticil-structure, 
but is organized into separate units or bodies, united in life into a jointed branching 
thallus, rather than the standard dasyclad single skeletal tube. Belzungia and 
Thyrsoporella are in fact identical in the plan of their peculiar lateral branch-structure 
within the calcareous wall-thickness. 

In the Middle East Thyrsoporella silvestrii Pfender is a common Eocene fossil. 
Rarely, there occur isolated examples whose external morphology suggests reference 
to Belzungia. The best example seen of this was a specimen, from the Middle Eocene 
Pila Spi Limestone of Koi Sanjak, Erbil Liwa, Northeast Iraq. The dimensions are 
however those of a Thyrsoporella rather than of the larger Belzungia. L. Morellet, in 
an unpublished pioneer report of January 1931, compared a similar specimen from 
the Palaeocene of the Sulemania district (N.E. Iraq) to the smaller of the French 
Eocene species, B. terquemi Morellet, but the enlargement on the micrographs given 
him was inaccurate, and measurement of the actual specimen shows that it was 
smaller. 

Note. Part 2 of Massieux (1966b), in which this author compares Thyrsoporella 
and Belzungia in detail, and refers T. silvestrii to Belzungia, was seen too late for 
proper discussion in this work. However, the specimens studied in the present work 
show the heavily-calcified walls of Belzungia, but the branch-system appears like 
that of Thyrsoporella. 

Genus BROECKELLA L. & J. Morellet 1922 

Diagnosis (after Morellet). Hollow calcareous units, keg-shaped, traversed along 
the axis by a tube open at the extremities. Annular cavity between the outer walls 



26 CALCAREOUS ALGAE OF THE MIDDLE EAST 

and tube-walls, divided by horizontal floors into successive compartments, each of 
these itself divided by radial septa into several chambers each communicating by a 
single pore with the axial tube, and by numerous pores with the exterior, riddling the 
outer wall. Pores opening in the axial tube set in regular verticils ; external pores 
set in irregular sinuous lines. 

Broeckella is a peculiar dasyclad described by Morellet (1922) from the Belgian 
Montian, and subsequently recognized from about the same level in Austria and Cuba 
(Keijzer 1945). These occurrences are of the type-species, B. belgica Morellet : 
B. ranikotensis (Walton) is known from the Indian Palaeocene (Walton 1925 ; Pia 
1928), and the little B. minuta Carozzi from Switzerland is presumed Palaeocene. 

Broeckella as described by Morellet (1922) is an extinct dasyclad whose skeletal 
remains occur as little keg- or short barrel-shaped units. Each unit contains a fairly 
wide central canal extending vertically from end to end, which once housed the main 
stem-cell of the plant. The apparently thick structure between outer surface and 
inner central canal is hollow, being divided by thin horizontal platforms into annular 
cavities, which are themselves divided into segment-shaped chambers by thin radial 
vertical walls. Each of these chambers (primary branches) communicates with the 
exterior by numerous small pores in the outer wall, said to open in sinuous lines, and 
with the interior canal by one large pore each, through the inner wall, arranged in 
horizontal rings. The distinctive thin-section appearance has been very well figured 
by Keijzer (1945). The numerous relatively large interior cavities between inner 
and outer walls have irregular surfaces to septa and partitions, made still more so by 
secondary calcification, and random cuts give curious irregular-radial patterns not 
like those of more conventional dasyclads such as Cymopolia, where there is a greater 
proportion of wall-material to original cavity in life. 

The wide but scattered Tethyan distribution of this genus, its probable ancestry 
and its restricted geological range have been discussed (Elliott 1962b) ; I concluded 
that it was a primitive genus occurring uncommonly even under optimum algal 
conditions in the Palaeocene, and then becoming extinct. 



Broeckella belgica L. & J. Morellet 
(PL 3. fig. 1) 

1922 Broeckella belgica Morellet : 22, pi. 2, figs. 56, 57. 

1945 Broeckella belgica Morellet ; Keijzer : 178, pi. 6, figs. 84-86. 

i960 Broeckella belgica Morellet ; Elliott : 225. 

1962 Broeckella belgica Morellet ; Elliott : 51. 

Descriptions. The characters of this, the type-species, are those of the genus. 
The Middle Eastern material consists of random thin-sections only, similar to 
Keijzer's Cuban material. Of described species, the Indian B. ranikotensis (Walton) 
is the largest, and the Swiss B. minuta the smallest : the Belgian Cuban and Middle 
East specimens are all referred to B. belgica Morellet. Some dimensions for com- 
parison are listed below. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 

Measurements and detail of Broeckella spp. Dimensions in mm. 



27 





belgica 


belgica 


belgica 


ranikotensis 


minuta 




(type) 


(Cuba) 


(M.E.) 






Length of unit 


i-3 


up to 2-0 


1 04 


3-5-5-° 


0-45-0-90 


Outer diam. of unit 


i-8 


1-4-2-5 


I-IO 


2-0-2-5 (max) 


0-25-0-45 


Central canal diameter 


o-6 


0-35-0-8 


0-4 


0-66-0-83 (max) 


0-05-0-15 


No. of verticils per unit 


4 


4-6 


4 


20 approx. 


numerous units 
(fused) 


No. of primary branches 












per verticil 


8-12 


10-15 


12 appr. 


15-20 


15-20 



Horizon. Palaeocene of Europe, Cuba and Middle East. 

Material. Random thin sections from the Palaeocene Sinjar Limestone of 
Kashti, Sulemania Liwa, North-east Iraq, and from the Palaeocene of Sahil Maleh, 
Batinah Coast, Oman, Arabia. 

Remarks. Both these occurrences are in rocks yielding a varied and character- 
istic Palaeocene algal microflora, as well as typical foraminifera for this level. 



Genus CLYPEINA Michelin 1845 

Diagnosis. Flat, saucer-, bowl- or funnel-shaped calcareous discs formed of 
horizontally-fused radial tubes : centrally they meet in a stout calcareous ring, each 
tube communicating by a single pore with the central cavity : the central ring is 
thickened below by the fused bases of the radial tubes and sometimes a smaller 
similar feature shows on the upper surface. In life these were the calcified structures 
of fertile dasyclad whorls. 

Clypeina occurs as small fossil calcareous discs, saucer-, bowl- or funnel-shaped, 
centrally perforate, and with the solid portion composed of fused radiating tubules : 
communicating each by a single core with the central cavity. Usually the discs are 
separate, but occasionally several occur together in vertical, consecutive association. 
Described by Michelin (1845 : 177) from the French Oligocene as a coral, it was sub- 
sequently referred to other marine invertebrate groups by various authors until 
Munier-Chalmas (1877), in a brief communication, drew attention to its true algal 
nature. 

Clypeina was reconstructed from Eocene material to show the probable structure 
and appearance of the plant in life (Morellet & Morellet 1918). These authors 
showed a dasyclad with central stem-cell bearing whorls of thin hair-like sterile 
branches below, and fused calcified cuplike fertile whorls above, each fertile whorl 
partially embracing the next : the plant is completed by a tuft of hair-like branches 
forming the terminal umbel, calcified at the base to give a perforate, " pepper-pot 
top ", structure (Fig. 3). The Morellets worked on loose, dissociated, elements from 
the unconsolidated sediments of the Paris Basin, and besides typical fertile whorls 



28 



CALCAREOUS ALGAE OF THE MIDDLE EAST 




Fig. 3. Reconstruction (after Morellet 1918) of Clypeina. 
(calcified) whorls above, terminal tuft at top. 



Sterile whorls below, fertile 
X 30 approx. 



they had calcified evidence of the sterile portion of the plant, of the lower, atypical 
fertile whorls, of the terminal structure, and of the serial association of the fertile 
whorls. 

Pia (1927) placed Clypeina in the tribe Diploporeae, and he was followed in this 
attribution by Emberger (1944) and Kamptner (1958). The Morellets (1913 : 31 ; 
1918 : 102), students of Tertiary and Recent algae, grouped Clypeina under Acet- 
abulariae with Halicoryne, Acetabularia and Acicularia, three genera still surviving, 
and all showing separate sterile and fertile whorls and of somewhat similar mor- 
phology. Rezak (1957) summarizing this, agreed with the Morellets in their attribu- 
tion. Clypeina is now placed in a new tribe Clypeineae, for its geological appearance 



CALCAREOUS ALGAE OF THE MIDDLE EAST 29 

precedes the evolution of the choristospore structures with which the terminal discs 
of Acetabulariae have been thought homologous. It therefore seems probable that 
it represents an earlier development of similar morphology, but from a different 
source. This point is more fully discussed below under dasyclad evolution (p. 99). 
In the Middle East Clypeina is represented by species in the Upper Jurassic and 
basal Cretaceous, and again in the older Tertiary (Palaeocene and Eocene). A 
clypeiniform alga, still incompletely known, occurs in the Permian, and a Triassic 
species is now known from elsewhere (Pantic 1965). The numerous species listed 
throughout the Cretaceous succession in the western Mediterranean area (Algeria, 
France, etc.) by Emberger (1957) have not been noted in Middle Eastern material 
during the examination of thousands of thin-sections, often richly algal, and in fact 
only three records occur for this portion of the geological column. 



Clypeina jurassica Favre 
(PI. 3, figs. 2-5 ; PI. 4, figs. 4, 5, 6) 

1927 Clypeina jurassica Favre : 34, pi. 1, figs. 2, 3 ; text-figs. 10, 11. 

1932 Clypeina jurassica Favre ; J. Favre : 12, text-fig. 2. 

1951 Clypeina jurassica Favre ; J. Morellet : 399, pi. 22. 

1955b Clypeina jurassica Favre and C. hanabatensis Yabe & Toyama ; Elliott : 125. 

1958a Clypeina jurassica Favre ; Donze : 21. 

1962 Clypeina jurassica Favre ; Powers : 131. 

Description (from Middle Eastern material). Discs (fertile verticils), saucer to 
open-funnel shaped, diameter up to 2-4 mm., height up to 0-75 mm. composed of up 
to 24 fused radiating tubules (sporangial elements) around a central cavity of up to 
0-5 mm. ; the majority of normal specimens are about 2-0 mm. diameter, with 18-20 
tubules and central cavity of about 0-4 mm. The tubules widen slowly outwards, 
and the outer ends are open : on the external surfaces, upper and lower, the tubules 
are demarcated by shallow grooves. Although in normal specimens the tubules are 
nearly circular in cross-section, they tend to vary according to the size of the disc of 
which they form part, and in the larger examples, with more numerous tubules, the 
tubule cross-section shows the height greater than the diameter. The tubules fuse 
to form a conspicuous thickened central basal ring on the lower surface of the disc : 
this is most developed in the funnel-shaped examples. In a large example of 
estimated 2-5 mm. disc-diameter or more, the inner diameter of a single tubule 
increases from 0-130 mm. near the centre to 0-390 mm. in 1 mm. tubule-length : 
the diameter of the single inner communicating pore between central cavity (stem- 
cell) and tubule is 0-050 mm. ; and the single wall-thickness about the middle of the 
tubule is 0-065 mm - I n random thin-section the united walls, back to back, of any 
two adjacent tubules show as radial fibrous calcite, clear or yellow, separated by a 
dark fine, and in horizontal (transverse) sections these median structures project 
radially at the margin, to give a torn serrated appearance to the whole disc. This 
wall-structure and the open ends of the tubules, whatever their significance in terms 
of the original plant-calcification or subsequent diagenesis, are characteristic of the 



30 CALCAREOUS ALGAE OF THE MIDDLE EAST 

species, whether preserved in limestone or marl, and there is normally no confusion 
with the Valanginian species C. lucasi Emberger. 

Horizon. Upper Jurassic ; circum-Mediterranean and Middle East. 

Material. Numerous solid and thin-section specimens from Qatar Peninsula, 
Persian Gulf, where it is abundant in the subsurface Upper Jurassic " Arab Zone " 
(Fahahil and Qatar Formations : Sugden in press) probably of Kimmeridgian- 
Tithonian age. Also at the same level in north-eastern Saudi Arabia (Powers 1962), 
and in Gezira no. 1 well, Murban, Abu Dhabi, Trucial Oman. Associated micro- 
fossils are the alga Salpingoporella annulata Carozzi and the microcoprolite Favreina 
salevensis (Pare^jas). Thin-section material from both Kirkuk and Samawa, Iraq, 
where it abounds likewise in the subsurface Najmah Formation, of about the same 
age, with the same companions. Also seen in thin-sections from the topmost 
Jurassic at Haushi, Southern Oman, Arabia, accompanied by debris probably 
referable to Griphoporella perforatissima Carozzi, an alga initially described from the 
Upper Portlandian and Berriasian of Switzerland. The species is common in the 
Upper Jurassic of numerous exposures in southern Persia (Gollestaneh Coll.). 

Remarks. Clypeina jurassica is a common microfossil in the Upper Jurassic of 
southern and central Europe, North Africa and the Middle East, and records of it are 
very numerous. Described by Favre (Favre & Richard 1927) on thin-section 
material from Switzerland, and re-described for comparison with Clypeina inopinata 
(Favre 1932), the next advance was the description of Algerian material by Morellet 
(1951) based on both thin-section and solid (silicified) specimens. Donze (1958a) 
re-described material from the type-area from a good selection of solid specimens, 
presumably isolated by weathering or artificial breakdown of weathered material. 
For the present study of Middle East examples both numerous thin-sections and 
solid examples obtained by washing of crumbled core-material have been available. 

The descriptions drawn up for this species by Favre, Morellet, Donze and myself 
all differ slightly in detail. The principal difference is that specimens from the type- 
area (Switzerland) show a lesser maximum number of sporangial tubules per verticil 
than do those from some other localities. For Swiss material Favre gives a relevant 
count of 10-17, an d Donze 7-17, whereas Morellet, with Algerian examples, gives 
11-20, and the Middle East material (above), shows up to 24. Although there are 
numerous figures in the literature of random cuts of this species conforming in this 
particular with the type-material, there are some which indicate a higher count 
(e.g. de Castro 1962, pi. 18 ; Italy, Naples area). These higher counts are from 
more southern areas than that of the type-material. It would seem that this is a 
case where the historical development of western Europe has resulted in the original 
description of Tethyan material being made in a marginal area, a phenomenon 
familiar both in stratigraphy and palaeontology. 

Other differences observed in the Qatar (Middle East) specimens were the some- 
what variable convexity of the verticils, and the prominence of the central thickened 
ring on the lower verticil surfaces. The former was however recorded by Donze on 
topotype material, and indeed is to be expected from our understanding of the growth 



CALCAREOUS ALGAE OF THE MIDDLE EAST 31 

of the living Acetabularia. The latter character was described by Morellet, but not 
well figured, on Algerian material. 

The pioneer study on Middle East (Qatar) material was by F. R. S. Henson in an 
unpublished report of 1942. He distinguished a minority of C. jurassica conforming 
strictly with the type-description, and more numerous examples with a higher 
sporangial-tubule count. In a preliminary examination of Middle East algae 
(Elliott 1955b) I recorded these latter as C. cf. hanabatensis Yabe & Toyama, com- 
paring them with this Japanese species which has a higher count (22-24, U P to 27), 
but is a larger species (verticil-diameter up to 3-5-4-0 mm.). This determination 
is now abandoned. 

Detailed comparative statistical studies of local populations of Clypeina jurassica 
from different circum-Mediterranean and Middle East countries have not been made 
to my knowledge. Such studies would have to be made on good collections of 
complete, isolated, verticils, since the recognition of proportional, as opposed to 
structural, differences, in random thin-section material is a task of great difficulty, 
at any rate with the small degree of difference expected in the present problem. The 
results would have to be interpreted in the light both of presumed salinity changes, 
from facies and accompanying fauna, a factor affecting living algae, and also bearing 
in mind possible post-mortem sorting of verticils of slightly differing size and shape 
from mixed assemblages of dissociated component-verticils derived from associated 
plants. It seems likely that the local differences revealed, at any rate in the main 
Tethyan basin, would depend on these secondary factors rather than on a progressive 
evolutionary trend. 

C. jurassica is a frequent and characteristic fossil for much of the Upper Jurassic 
of the western old-world Tethys ; in the east, it is missing from rocks of this age in 
Borneo. The oldest level appears to be in Algeria (Rauracian-Sequanian of Morellet 
1951, equalling Upper Oxfordian of current usage) ; the species occurs throughout 
the Mediterranean Kimmeridgian and is especially abundant at levels of Portlandian 
or Tithonian age over the whole of its distribution-area. In my experience it extends 
to the very top of the Upper Jurassic and is a good index-fossil for the upper part of 
the Upper Jurassic. (See also comments below (p. 87) on the Jurassic-Cretaceous 
boundary.) 

In the Franco-Swiss area, from which the types were described, there are records 
from the lowest Cretaceous (infra- Valanginian and Berriasian, e.g. Donze 1958a, b). 
This is in an area adjacent to a region of uplift with terminal Jurassic — early Creta- 
ceous freshwater brackish and lagoonal beds of Purbeck type : the algae are con- 
sistently smaller than those from the Jurassic. They may be a transitional form to 
the succeeding C. inopinata (rare or absent in the Middle East), their evolution a 
reaction to salinity-changes. Donze suggested, that they were either a different 
species, close to C. inopinata, or stunted C. jurassica " bad adaption to environ- 
ment ". The relation of these and other algae to salinity is discussed below under 
environment. In Jugoslavia Kercmar (1962) has described a local variety C. 
jurassica minor, which he distinguishes from the typical C. jurassica jurassica mostly 
by the smaller size, there being little if any overlap or transition in this character. 



32 CALCAREOUS ALGAE OF THE MIDDLE EAST 

He regards this small variety as possibly transitional to C. parvula. It certainly 
seems that C. jurassica was the rootstock for other and later species, and that this 
evolution may well have been connected with areas of late- Jurassic uplift and 
emergence. 

Clypeina inopinata Favre 1932 

This species, described by Favre (1932) as distinct from C. jurassica and as 
succeeding it in the Swiss Valanginian, is not known to me with certainty from the 
Middle East, although basal Cretaceous is well-represented in available collections. 
Occasional qualified records in unpublished reports are based on rare and frag- 
mentary Clypeina sp., and no good C. inopinata have been noted. The species may 
be a local successor to C. jurassica in the Franco-Swiss area only. M. Dufaure of 
Bordeaux informed me (personal communication 1965) that the type-occurrence of 
C. inopinata is, in fact, Upper Berriasian i.e. pre- Valanginian. 

Clypeina lucasi Emberger 
(PI- 5, ng. 4) 

1956 Clypeina lucasi Emberger : 549, pi. 24, f. i, 2, 7. 
i960 Clypeina lucasi Emberger ; Elliott : 223. 

Description (after Emberger). Fertile verticils almost flat, circular, diameter 
2-5-3-0 mm. and about 0-5 mm. thick : 12-18 club-shaped sporangial chambers, of 
about i-i mm. long and max. diameter 0-5 mm., fused laterally for § of their length, 
separated by shallow grooves, and terminally imperforate. Central cavity of 
0-35-0-48 mm. diameter, margined by a feeble raised ring above and a more promi- 
nent one below. 

Horizon. Valanginian of Algeria and Oman. 

Material. Thin-sections in basal Cretaceous limestones (Thamama Formation 
Equivalent), Hugf area, southern Oman, Arabia. 

Remarks. This distinctive species was described by Emberger (1956) from solid 
(silicified) specimens found in the Algerian Valanginian, where it was accompanied 
by Clypeina marteli Emberger, also new. In the Middle East the two species occur, 
together with the codiacid Arabicodium aegagrapiloides Elliott, at the same level in 
Southern Oman, Arabia. In the thin-sections of limestone C. lucasi may be recog- 
nized, the details corresponding with much of Emberger's description. 

Clypeina marteli Emberger 

(PI. 4) fig- 1) 

1956 Clypeina marteli Emberger : 550, pi. 24, f. 3-6. 
i960 Clypeina marteli Emberger ; Elliott : 223. 

Description. Stellate verticils, gently curved, diameter 1-2 mm., consisting of 
from 7 to 12 radiating tubules, fused laterally for about the inner third of their length 
and then free outwards, surrounding an inner circular cavity of from 10-14% of the 



CALCAREOUS ALGAE OF THE MIDDLE EAST 33 

verticil diameter. Tubules circular in cross-section, terminally bluntly rounded, 
thin-walled (wall-thickness 0-026 mm. in a tubule of outer diameter 0-130 mm. ; 
verticil-diameter 1-5 mm. approx.), and forming a moderately developed raised 
central ring below, but without similar feature above : the tubules communicate 
with the central cavity each by a single pore. 
Horizon. Valanginian of Algeria and Oman. 

Material. Found in the basal Cretaceous (Lower Thamama equivalent) of 
Hugf, Southern Oman, Arabia, i.e. at about the same horizon as the type-level in the 
Algerian Valanginian, and similarly associated with Clypeina lucasi Emberger, and 
also with the codiacid Arabicodiurn aegagrapiloides Elliott. 

Remarks. Clypeina niarteli is highly distinctive amongst species of its genus : 
the only other stellate species in which the radiating tubules are similarly free for 
much of their length are Clypeina digitata (Parker & Jones) Morellet emend. Rezak, 
and (less closely comparable) C. helvetica Morellet, both Eocene. Emberger's com- 
parison with the former drew attention to the gently concave plane of C. marteli as 
compared to the more funnel-shaped form of C. digitata, a valid distinction (Emberger 
1956). C. marteli, however, does show a central fusion ring, marginal to the stell-cell 
cavity, on its lower surface, though this is regular in form and not irregular as that of 
C. digitata described by the Morellets (1913). 

More serious risk of confusion exists with Actinoporella podolica Alth, which 
similarly occurs at about Valanginian level in the Middle East. However, although 
both are somewhat similar in size, Actinoporella shows many more tubules per 
verticil (18-20 as opposed to 7-12, and the former smaller in size), and a propor- 
tionally larger central cavity (d/D 20% or more, as opposed to 10-14% m C. marteli). 



Clypeina parvula Carozzi 

(PL 5, figs. 5, 6) 

1946 Clypeina parvula Carozzi : 24, fig. 1. 

1948 Clypeina parvula Carozzi ; Carozzi : 355, figs. 50, 51. 

1955b Clypeina parvula Carozzi ; Elliott : 126. 

i960 Clypeina parvula Carozzi ; Elliott : 222, 223. 

Description (after Carozzi). Sterile whorls in the form of straight thick-walled 
calcareous tubes, widening in the upper portion and with the outer surface showing a 
number of shallow straight vertical flutings or concavities, usually about twelve, but 
from ten to twenty-five recorded. The fertile whorls are similar but widen much 
more, terminating in a kind of peripheral fringe or collar : internally, sporangial 
chambers correspond to the external flutings, the actual cavities being set in the thick 
calcareous wall. External diameter is said to be from 0-09-0-45 mm. and the 
diameter of the central canal 0-03-0-12 mm. (average 0-07 mm.). 

Horizon. Upper Jurassic — bottom Cretaceous Europe (PAptian-Albian Jugo- 
slavia, see Radoicic i960), bottom Cretaceous Middle East. 

Material. In Iraq, from the lower part of the Cretaceous (about Valanginian 



34 CALCAREOUS ALGAE OF THE MIDDLE EAST 

level) : Sarmord Formation of Jebel Gara and Garagu Formation of Banik (both 
Mosul Liwa) ; also subsurface Garagu at Kirkuk. 

It has also been seen in the bottom Cretaceous at Haushi, Southern Oman, Arabia, 
where it was accompanied by the dasyclads Acicularia, Salpingoporella, and Gripho- 
porella, also by Permocalculus : the level was independently dated by foraminifera. 

Remarks. The details given above are summarized from Carozzi's descriptions. 
His reconstruction shows a somewhat peculiar little alga, consisting of inverted 
fluted cones inserted within one another vertically. His thin-sections substantiate 
the detail quoted above and also show further detail. This species, if correctly 
interpreted as a Clypeina, departs more from the usual verticil-morphology than 
other species. In the Swiss Purbeckian (terminal Jurassic) C. parvula occurs in 
beds interpreted as freshwater, its companion fossils being charophytes and 
ostracods. 

In the bottom Cretaceous, marine Valanginian level, of the Middle East there 
occur not uncommonly in thin-section preparations sections corresponding mostly 
to the transverse cuts of the bases of verticils as figured by Carozzi. Occasionally 
vertical cuts are seen, but never the transverse cuts he figures of the upper portions 
of fertile verticils, which show the sporangial cavities, outer collar, and other detail. 
The number of flutings is usually from 8 to 10, and the size-range falls for the most 
part in that quoted above from Carozzi, though one large example had an external 
diameter of 0-6 mm. 

These little fossils, with occasional charophytes and ostracods, occur in Iraq to 
form a subordinate element in a rich marine dasyclad and other algal flora, which 
includes species of Actinoporella, Cylindroporella, Salpingoporella, Permocalculus, 
Lithocodium etc., also foraminifera and microproblematica, marine mollusca and 
corals. They are interpreted as Clypeina parvula from coastal freshwater beds, 
which, together with the charophytes, have been washed out to sea before burial. 
Only the more resistant parts of the verticils survived this derivation, which would 
explain the absence of the more fragile reproductive structures. 



Clypeina spp. (Cretaceous) 
i960 Clypeina spp. Elliott : 225. 

Three records only of the genus may be made for the whole of the Cretaceous 
examined above the basal portion (Berriasian-Valanginian) yielding the species 
already described. 

The specimen figured as " Munieria baconica Deecke " (Elliott 1958, pi. 48, fig. 1) 
is not of this species and may be a Clypeina ; it comes from the Aptian-Albian of 
Surdash, Sulemania Liwa, Iraq. 

Another occurrence is in the Cenomanian, subsurface Mahilban Formation of 
Fallujah Well, Dulaim Liwa, Iraq. Fragmentary material indicated a Clypeina sp. 
of estimated whorl-diameter 3-25 mm., showing approximately 50 fused adjacent 
sporangial tubules of 1-04 mm. length, circular in cross-section and of 0-36 mm. near- 



CALCAREOUS ALGAE OF THE MIDDLE EAST 35 

terminal external diameter and 0-23 mm. internal diameter. This material is 
insufficient for description, and it is not known if it corresponds with any of the 
undescribed Cenomanian species listed by Emberger (1957). The remains were 
associated with fine debris of codiacid algae. 

A third Cretaceous Clypeina occurred higher, in the Maestrichtian (Shiranish 
Formation) of Diyana, Rowanduz Liwa, Iraq. It showed only a transverse section 
of sporangial tubules of about 0-13 mm. diameter. This is quite inadequate for 
comparison with such species as Clypeina sahnii Varma (1952) from the Danian of 
India. 



Clypeina merienda Elliott 
(PI. 4, figs. 2, 3, 7. 8) 

JO^b Clypeina merienda Elliott : 127, pi. 1, figs. 8, 9. 

Description. Fertile verticils disc-like, circular and flat, with diameter up to 
2-5 mm., and diameter of central cavity up to i-o mm. The verticils consist of about 
50 or more radiating hollow tubules, set nearly horizontally to the vertical axis, with 
the tubules united laterally and often slightly expanded at the periphery, where they 
are often open. Circular in cross-section, they have a transverse diameter of 0-15- 
0-18 mm. measured in the mid-zone of large examples, with internal diameter of 
0-072 mm., but examples with smaller diameters than this are common and there 
would seem to be some variation in this character. The expanded and open tubule- 
ends at the periphery are variable, and may be an indication of spore-shedding in 
mature whorls. Internally each tubule communicates by a pore with the central 
cavity : fused calcification forms a thickening in this central zone and extends down 
to the next whorl. Up to six whorls have been seen in serial association as in life : 
these whorls, measured vertically in the mid-zone of the tubules, from centre to 
centre of consecutive whorls, were from 0-34-0-52 mm. apart. 

Horizon. Palaeocene-Lower Eocene of the Middle East. 

Material. In northern Iraq, from the Sinjar Formation of Banik (Mosul Liwa), 
of Koi Sanjak (Erbil Liwa), and of Sirwan (Sulemania Liwa) ; also from the Kolosh 
Formation of Surdash (Sulemania Liwa). In southern Iraq, the species occurs in a 
fragmentary state in the Basita Beds of the Umm er Rudhama Formation (Palaeo- 
cene-Lr. Eocene) near Aidah, Diwaniyah Liwa. 

Remarks. This Clypeina is distinctive in the large number of radial tubules per 
whorl, in which character it somewhat resembles the larger Orioporella from the 
Belgian Montian and Indian Danian (Morellet 1922, Pia 1936b), but with no trace of 
the pores which perforate upper and lower surfaces of the tubules in this genus. 
C. merienda is larger than the Eocene Clypeina spp. described by the Morellets 
(1913 ; 1922) : the frequent flatness of its whorls is noticeable, though there is some 
variation in this character. Of Middle Eastern species, it is the one in which serially 
associated whorls, as in life, are most often seen in the fossils. 



36 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Clypeina sp. (Palaeocene) 
(PL 5. %. 2) 

i960 Clypeina. spp. Elliott: 225. 

Apart from C. merienda, there occur rarely in the Palaeocene-Lower Eocene of the 
Middle East small Clypeina spp. inviting comparison with those from the French 
Eocene described by L. and J. Morellet (1913 ; 1922 ; 1939 ; see also Rezak 1957). 
Random thin sections of these have been noted in material from the Palaeocene 
Sinjar Limestone of Banik, Mosul Liwa, northern Iraq ; from the Palaeocene 
Ghurna Beds (Umm er Radhama Formation) of Al Ghurra, Divvaniya Liwa, southern 
Iraq ; from the Palaeocene-Lower Eocene of Sahil Maleh, Batinah Coast, Oman, 
Arabia ; and from the Palaeocene of Aqabar Khemer, Hajar, Hadhramaut. The 
example figured is typical and shows a verticil of 1 mm. diameter, central aperture of 
0-36 mm. diameter, with about 22 adjacent sporangial tubules. None of these 
localities have yielded enough material for a precise determination by comparison 
with the similarly-sized, well-known and beautifully-preserved European material. 

? Clypeina sp. (Permian) 

(PI. 5, figs, i, 3) 

1958a Clypeina Mich, (ou genre nouveau tres voisin) Emberger : 51. 

i960 ^Clypeina sp. Elliott : 219. 

1965 Eoclypeina Emberger MS ; Glinzboeckel and Rabate : pi. 74. 

In a preliminary note on the Upper Permian of Djebel Tebaga, southern Tunisia, 
Emberger (1958a) listed a clypeiniform alga of which he proposes to describe three 
new species ; this has been illustrated but not described in Glinzboeckel and Rabate 
(1965). Debris of the same or a similar form is now figured from the Permian of 
Iraqi Kurdistan, where it occurs rarely at Harur (Mosul Liwa), both from the base 
of the Satina Evaporite formation and from the top of the Zinnar Formation 
immediately below. Whether this is a true Clypeina, ancestral form or homoeo- 
morph, it seems to represent an early attainment of the umbrella-like sporangial disc 
familiar in certain Mesozoic and Tertiary genera : it is hoped that M. Emberger's 
descriptions will throw light on this. The Jugoslav Permian dasyclads Salopekiella 
and Likanella (Milanovic 1965 ; 1966) bear no close resemblance, and nothing else 
associated is at all comparable. 

The recent description of Clypeina besici Pantic (1965) from the Upper Triassic of 
Jugoslavia is a valuable confirmatory link between the Permian Eoclypeina and the 
familiar Upper Jurassic C. jurassica. 

Genus CYLINDROPORELLA Johnson 

Diagnosis. Cylindrical calcareous bodies terminally tapered or rounded, 
interpreted as serial dasyclad units arranged in life somewhat similarly to those of the 
Recent Cymopolia. Internally the longitudinal central canal (stem-cell cavity) is 
surrounded by rings of proportionally large spherical sporangial cavities alternating 



CALCAREOUS ALGAE OF THE MIDDLE EAST 37 

with whorls of infertile primary branch-canals. These are normally at right angles 
to the longitudinal axis, and each divides terminally into secondaries. Sporangia 
and infertile branches alternate in position in successive whorls. 

Cylindroporella is a distinctive Mesozoic dasyclad first described by Johnson 
(1954b) : type-species C. barnesii from the Albian Edwards Limestone of Texas. 
Elliott (1957) described new species from both Upper Jurassic and Lower Cretaceous 
of the Middle East, and has since recognized C. barnesii there. The Jurassic species 
C. texana Johnson (1961a) and C. ellenbergeri Lebouche & Lemoine (1963), and the 
Upper Cretaceous C. elassonos (Johnson & Kaska, 1965), have not yet been identified 
from the Middle East. 



Cylindroporella barnesii Johnson 
(PI. 6, figs. 3, 4) 

1954 Cylindroporella barnesii Johnson : 788, pi. 93, figs. 1-7. 

Description. The characters of this, the type-species, are those of the genus. 
The table below gives the various measurements by which the three species recog- 
nized in the Middle East may be distinguished. 

Horizon. Albian of Texas : Lower Cretaceous of Iraq. 

Material. Fragmentary material referable to this species has now been recog- 
nized from two localities in Iraq : from the subsurface Garagu Formation (Valan- 
ginian-Hauterivian) of Makhul no. 2 well, Mosul Liwa, and from the Sarmord 
Formation (about Aptian level) at Sekhaniyan, Surdash, Sulemania Liwa. 

Remarks. Both the above occurrences show a Cylindroporella with outer 
diameter of 0-468 mm., inner diameter 0-156 mm., and sporangial diameter of 0-156 
mm. ; they are distinct from the larger C. sugdeni Elliott, which they overlap in 
range, and seem best referred to the type-species, described from the Albian. 

Detail of Cylindroporella spp. (M.E.). Dimensions (in mm.) 



Length of segment 
Diameter of segment 
Diameter of central canal 

Diameter of sporangia 

Number of sporangia per whorl Usually 6 in all three species 

Number of sterile branches per whorl Usually 6 in all three species 

Angle of branches to stem 90 ° in all three species 

Number of terminal secondary branches Probably 4 in all three species 

Vertical distance between whorls 0-13 01 7-0 -187 0-39 



arabica 


barnesii 


sugdeni 


i'43 


2-8-5-1 


3-o + 


o-3i-o-57 


0-38-0-55 


0-78-1 14 


variable ; 


0-08-0-15 


0-234-0-36 


0-052-0-230 






0-078-0-156 


0-134-0-189 


0-26-0-312 



38 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Cylindroporella arabica Elliott 

(PI. 6, figs. I, 2) 

1957 Cylindroporella arabica Elliott : 227, pi. 1, figs. 13-16. 
1962 Cylindroporella arabica Elliott ; Powers : 131. 

Description. This is the smallest of the Middle East species of the genus. C. 
texana Johnson, of about the same age from the U.S.A., shows smaller dimensions 
for internal structures but these occur in a very much longer slim segment. 

Horizon. Upper Jurassic of Arabia. 

Material. C. arabica occurs in the upper part of the Upper Jurassic, subsurface 
Arab zone, in the Dukhan wells, Qatar, Persian Gulf, also at the same level in north- 
eastern Saudi Arabia (Powers 1962), and in Gezira no. 1 well, Murban, Abu Dhabi, 
Trucial Oman ; associated algae are Clypeina jurassica Favre and Salpingoporella 
annulata Carozzi. It occurs at the same level, also with S. annulata, at Al Hamiah, 
coastal Wahidi, Hadhramaut. 

Cylindroporella sugdeni Elliott 
(PL 6, figs. 5-7) 

1957 Cylindroporella sugdeni Elliott : 227, pi. 1, figs. 1-6. 

Description. This species shows large, thick segments, with greater sizes for 
internal structures than other species, if the Liassic C. ellenbergeri Lebouche & 
Lemoine is excepted : this last differs in various characters from the more homo- 
geneous later species. C. sugdeni is proportionally shorter and much thicker than 
the type-species C. barnesii. 

Horizon. Lower Cretaceous of Middle East. 

Material. Described from the subsurface Lower Cretaceous of Fahud no. 1 well, 
Oman, Arabia, where it was abundant. It occurs in Orbitolina-limestone of probable 
Barremian-Aptian age at Wady Hajar and Wady Ghabar, Hadhramaut : also to 
the north in the subsurface Lower Qamchuqa Limestone (Hauterivian level) of 
Kirkuk no. 116 well, Iraq. 

Cylindroporella spp. 

There remain various records of indeterminate Cylindroporella, based on random 
cuts in thin-section, obviously of the genus, but not diagnostic of a species : often 
they are small in size. These have been seen in the Lower Cretaceous Qamchuqa 
Formation of Chama, Mosul Liwa, northern Iraq ; subsurface in the same formation 
at Barremian-Aptian level in Kirkuk well no. 116, and again at this level in the 
Lower Cretaceous of Wady Arus, Hajar, Hadhramaut. 

Genus CYMOPOLIA Lamouroux 1816 
Diagnosis. Thallus formed of consecutive hollow calcareous cylindrical bodies, 



CALCAREOUS ALGAE OF THE MIDDLE EAST 39 

terminally rounded ; in each the main longitudinal canal (stem-cell cavity) extends 
from end to end, the wall-thickness perforated by close-set more or less horizontal 
whorls or verticils of branch-canals. Each verticil consisting of several branch- 
systems of the same pattern : an inner primary branch dividing into several (usually 
four) secondaries, and one sporangial cavity, usually spherical : the secondaries 
reach the outer surface to give a dense pore-pattern. 

The dasyclad Cymopolia is well-known from living species in the warm waters of 
the East and West Indies. The plant shows a branched thallus of conventional 
" seaweed " pattern, in which the fronds are composed of heavily calcified serial or 
consecutive units, united by non-calcified tissue : each of these units corresponds in 
general plan to the single calcified tubes of the more normal dasyclad genera. After 
death the units come apart, and it is in this condition that they are met with in the 
fossil state, being known thus from the Upper Cretaceous onwards. 

Cymopolia anadyomenea Elliott 
(PI. 7 ; PI. 8, figs. 1, 5) 

1 959 Cymopolia anadyomenea Elliott : 218, pi. 1, figs. 1-4, 8. 

Description. Elongate hollow tubular units each showing several external 
horizontal annular flange-like swellings or increases of diameter, more or less regularly 
spaced, varying in development in different individuals : external surface finely 
patterned with small closely-set pores. Length (incomplete), up to 6 mm. seen ; 
diameter varying both with absolute size and relative flange-development, 1-5- 
3-9 mm. (usually 2-0-2-5 mm.). Internal diameter of the main cell-cavity either 
constant or variable : if the latter, waxing and waning to correspond with external 
diameter-changes, but to a lesser extent. The d/D ratio varies correspondingly from 
50-70%, being almost always 50% or more : only with extreme external flange- 
development can a figure of less than 50% be obtained. The wall-thickness is 
perforated by numerous closely-set whorls or verticils of crowded branches, 45-48 
per verticil, and about 6 verticils per 1 mm. measured vertically. Each primary 
branch gives rise to a globular sporangium of 0-05-0-08 mm. diameter and four or 
more secondary branches set at an angle of 45-60 ° from the horizontal. The branch- 
systems are coarser at flange-levels, where the diameters of primary and secondary 
branches were 0-065 mm - an d 0-039 mm - on a large specimen, and 0-039 mm. and 
0-026 mm. on a small specimen. 

Horizon. Maestrichtian of Northern Iraq and Afghanistan ; possibly from 
Maestrichtian of Tibet. 

Material. Upper Aqra Formation (Maestrichtian) of Aqra and of Chalki Islam, 
Hadiena Formation of Chalki (top Senonian), Upper Bekhme Formation (Maestrich- 
tian) of Chia Gara, and Aqra-Bekhme Formation of Gal-i-Mazurka, all five limestone 
localities in Mosul Liwa. Also in the green-rock sands (Tanjero Formation, Maes- 
trichtian) of Diza, Erbil Liwa. 

Remarks. This Cymopolia may be distinguished from other species of the genus 
by the peculiar annular flanging of the calcareous units. This " waxing-and 



40 CALCAREOUS ALGAE OF THE MIDDLE EAST 

waning " growth suggested a half-way stage between the ordinary single tubular 
dasyclad and the living segmented Cymopolia, but it seems much more likely that 
the units are in fact segments themselves, as in other species, and that the frequent 
broken pieces found are due to ordinary post-mortem mechanical fracture. The 
number of sporangia per verticil (45-48) is high and gives a very crowded appearance 
to this fossil in section, when compared with similarly-sized C. barbata (L.) Lmx. 
(Recent) and C. elongata (Defr.) Mun.-Chalm. (Eocene), in both of which the count 
is about 30. 

The flanged units give outlines of striking appearance in random thin-section. It 
was in this condition, recrystallized in limestones, that they attracted my attention, 
but no description was possible until material with the internal structures well- 
preserved was discovered in the green-rock sand facies of the same age. In Tibet, 
the Cymopolia sp. of Morellet (1916 : 49; Maestrichtian of Kampa Dzong) may 
possibly be this species, as C. tibetica Morellet is associated with C. anadyomenea in 
Iraq. 

Although C. anadyomenea is thus distinctive for the Maestrichtian, an apparent 
homoeomorph occurs in the Lower Cretaceous of Italy (Praturlon 1964). This is not 
yet fully described due to scarcity of material, though it appears to differ in flange- 
profile. This or a similar species occurs also in the Lower Cretaceous of Borneo (Bau 
Formation), and in the Lower Cretaceous of Jugoslavia (Radoicic in Hit.). 



Cymopolia eochoristosporica sp. nov. 
(PI. 9, figs. 1-3) 

Description. Tubular cylindrical thickwalled units of about 2-0-2-2 mm. 
external diameter (maximum seen 2-42 mm.), internal diameters 0-73-0-86 mm. 
(maximum seen 0-91 mm.), giving a d/D ratio of 36-40%. Estimated lengths of 
units up to 9 or 10 mm. Verticils of 12-14 primary branches which are probably 
inclined upwards at a low angle from the horizontal. Each branch communicates 
with the stem-cell by a very short connecting pore of 0-03-0-04 mm. diameter. 
These pores are set about 0-26 mm. apart measured (vertically) along the stem-cell 
walls. The branch then expands into the main swollen portion, seen as rounded- 
rectangular in near-vertical section, where it measures 0-390-0-416 mm. radially 
and 0-234 mm - vertically. These swollen portions occupy much of the thickness of 
the walls and are thus very close-set, the interstices being only 0-030 mm. thick. 
Finally each swollen portion divides into a small cymopoliform cluster of one 
spherical sporangium and four divergent secondary sterile branches. Diameter of 
the sporangium is 0-13 mm. ; and the diameter of the short neck or pore connecting 
it with the swollen primary is 0-052-0-065 mm. The secondaries have a median 
diameter of 0-040-0-052 mm. and expand terminally at the outer surface to shallow 
depressions of about 0-104 mm - diameter. 

Horizon. Maestrichtian of Trucial Oman, Arabia. 

Holotype. The specimen figured in pi. 9, figs. 1, 2 from the subsurface Aruma 



CALCAREOUS ALGAE OF THE MIDDLE EAST 41 

Formation (Maestrichtian level) of Murban No. 53 well, Abu Dhabi, Arabia. V. 
52652. 

Syntype. The specimen figured in pi. 9, fig. 3, same locality and horizon as for 
holotype. V. 52653. 

Other Material. Several incomplete random thin-sections, provenance as 
above. 

Remarks. This remarkable species does not at first sight appear to show the 
branch-structure of the genus Cymopolia. The large and conspicuous swollen 
primaries suggest a typically cladospore Mesozoic genus. However the small 
terminal cymopoliform branch-systems are distinctive. They are typically choristo- 
spore, and lead to the conclusion that the species shows one possible transition 
between cladospore and choristospore organization. Typical C. tibetica of the same 
geological age show expanded primaries, but to a very much less degree, and this 
feature survives not uncommonly in the Tertiary subgenus Karreria, and even 
occasionally in specimens of living Cymopolia (see remarks above under C. tibetica). 
In these later forms this character is best regarded as vestigial. 

C. eochoristosporica appears to show the cladospore/choristospore transition by the 
appearance of a small choristospore development superimposed on the large clado- 
spore branch, presumably with partial transference of sporangial contents. In this 
connection it is as remarkable an evolutionary record as Pia's suggested interpreta- 
tion of his forms trichophora and vesiculifera of the Triassic Diplopora annulata as 
endospore and early cladospore respectively. Here the transition from endospore to 
cladospore is similarly considered to have taken place within the one species, but the 
separate characters are shown in different individuals with a possible geographical- 
environmental distribution of the two forms. The scarcity of my Maestrichtian 
Cymopolia spp., when compared with Pia's abundant Triassic diplopores, precludes 
an investigation of this possible subsidiary parallel for the present. Moreover, 
Herak's review of Pia's work on this subject (Pia 1920 ; Herak 1957), whilst clearing 
the taxonomic confusion involved, also shows the many uncertainties which attend 
evaluation of the Triassic species in its varied forms and occurrences, even with an 
abundance of material for study. 

For these reasons the limited material now studied is described as a new species, 
the available individuals showing clearly in their morphology the characters on which 
the species is based. 

Cymopolia tibetica Morellet 

(PI. 8, figs. 3, 4) 

1916 Cymopolia tibetica Morellet : 47, pi. 15, fig. 10, text-figs. 14-21. 

1927 Karreria tibetica (Morellet) Pia : 83. 

1940 Cymopolia tibetica Morellet ; Pfender : 234. 

i960 Cymopolia tibetica Morellet ; Elliott : 223. 

Description (summarized from Morellet) . Cymopolia with rather straight-sided 
cylindrical units of up to 2-5 mm. long and diameters from i-i to 1-5 mm., diameter of 



ji CALCAREOUS ALGAE OF THE MIDDLE EAST 

central canal about 50% external diameter, external surface when unworn showing 
pattern of nearly uniform circular pores, but when worn showing pores of two sizes, 
the larger being the sporangial chambers. In the verticils, the normal branch- 
pattern of each primary giving rise to one spherical sporangial cavity and four 
secondaries is modified by the distal portion of the primary branch being greatly 
expanded immediately before branching into sporangium and secondaries : these 
additional cavities are conspicuous in vertical and transverse section. 

Horizon. Maestrichtian of Tibet, northern Iraq, Turkey and Arabia. 

Material. In northern Iraq, in the Aqra Formation of Aqra and of Zibar 
Isumeran, in the Hadiena Formation of Chalki, and in the Aqra-Hadiena develop- 
ment of Chalki Islam, all in Mosul Liwa, in limestone facies. The species is also 
known from the clastic Tanjero Formation of Diza, Erbil Liwa, and recorded by 
Naqib (i960 : 176), as a derived fossil, in pebbles occurring in Palaeocene con- 
glomerates (Kolosh Formation) at Argosh, Mizuri Bala area, Mosul Liwa. Seen also 
in subsurface Maestrichtian at Murban, Abu Dhabi, Arabia. 

Remarks. This species occurs not uncommonly in the Maestrichtian of Iraqi 
Kurdistan, usually in the limestone facies. Specimens are small (external diameter 
0-75-0-85 mm.) and very often fragmentary, but show the distinctive characters of 
the species in section. The Zibar-Isumeran specimens are in the worn condition 
suggesting Neomeris or Larvaria as described by Morellet in some Tibetan material. 
The type-material was from the Maestrichtian of Kampa Dzong, Tibet : Pfender's 
record is from Sofular, Ankara, Turkey. She regarded both this Turkish and the 
type Tibetan rocks as Palaeocene. In the type area the species comes from an 
unequivocally Maestrichtian bed (Douville 1916), and it is not clear from her sum- 
mary account which levels are represented at her Turkish locality. If the species 
was correctly determined, it seems likely that it is Maestrichtian in view of the Iraqi 
occurrences. 

Fragmentary remains of an indeterminate Cymopolia sp. have also been noted in 
the Maestrichtian of Oman. 

Pia's reference of C. tibetica to the Tertiary Karreria Munier-Chalmas was based on 
the former's recognition of this subgenus, not by the pyriform sporangia but by the 
expanded primary branches. Pfender, however, states that L. Morellet, dissecting 
Recent Cymopolia, found differences in this latter character between different 
segments of the same plant. In the present work Karreria is restricted to those 
Palaeocene Cymopolia showing pyriform sporangia. 

Cymopolia kurdistanensis Elliott 
(PI. 10, figs. 2-5) 

1055b Cympolia kurdistanensis Elliott : 127, pi. 1, figs. 13-15. 
i960 Cymopolia kurdistanensis Elliott ; Elliott : 225. 

Description. Tubular cylindrical thick-walled units with rounded ends : units 
variable in length and diameter relationship, length up to 4-0 mm., diameter com- 
monly about 0-75 mm. and exceptionally up to 1-5 mm. ; internal diameter (stem- 



CALCAREOUS ALGAE OF THE MIDDLE EAST 43 

cell) normally about 50% of external. Closely-set verticils of rather crowded 
branches, the internal openings of the primaries being 0-16-0-20 mm. apart measured 
vertically between successive whorls ; about 28 branches per verticil. Each branch 
shows a short primary of about 0-04 mm. diameter, directed upwards and outwards 
at about 60 ° from horizontal ; this gives rise to a single globular sporangial cavity 
of 0-10-0-13 mm - diameter (exceptionally larger), and to four secondary branches of 
0-026 mm. diameter at their thinnest. These extend outwards and upwards at a 
lesser angle than the primaries, and at the outer surface they widen conspicuously to 
occasion the external pattern of closely-set rounded polygonal depressions of about 
0-065 mm. diameter. 

Horizon. Palaeocene-Lower Eocene of Middle East. 

Material. In Iraqi Kurdistan, from the Sinjar Formation of Banik and Kani 
Masa, Amadia (both Mosul Liwa) and Koi Sanjak (Erbil Liwa), from the Kolosh 
formation of Bekhme and Rowanduz (both Erbil Liwa), and from the Kolosh 
Formation of Surdash and Sinjar Formation of Pila Spi (both Sulemania Liwa). In 
southern Iraq, Basrah area, poorly preserved subsurface Palaeocene Cymopolia are 
probably of this species. C. kurdistanensis occurs in the Palaeocene/Lower Eocene 
Umm er Rhudhama Formation of the southwestern desert near Aidah, Diwaniyah 
Liwa. In south-east Arabia, from the Palaeocene of Jebel Abiad, and from the 
Batinah Coast, both Oman ; and from the Palaeocene of Jebel Faiyah, Sharjah, 
Trucial Oman. Very numerous fragmentary Cymopolia in the Palaeocene-Lower 
Eocene of the Middle East are probably referable to this, the commonest species. 

Remarks. Cymopolia kurdistanensis is a distinctive but typical species of its 
genus. Like the common European C. elongata (Defr.) Mun.-Chalm., it varies much 
in segment-size and proportions. It is, however, a smaller species ; L. & J. Morellet 
(1913 : 11) describe C. elongata segments as large as 12 mm. by 2-5 mm., and in this 
species the distance between successive whorls is larger (0-23-0-26 mm.) than found 
in C. kurdistanensis. An important difference lies in the secondary branches. The 
terminal widening described above for C. kurdistanensis does not occur in type area 
(Paris Basin) C. elongata. Hence the Middle East species shows an external pattern 
of shallow rounded-polygonal depressions (PI. 10, fig. 2) whereas the European 
species is externally set with more abruptly-opening fine pores (PI. 10, fig. 1). This 
is not a difference due to wear and tear, since abrasion of C. kurdistanensis would give 
a pattern more like that of C. elongata, and the European species is often perfectly 
preserved. 

The Central American Eocene species C. mayaense (Johnson & Kaska, 1965) is said 
to be similar to C. kurdistanensis and C. elongata. 

C. kurdistanensis is abundant at the localities listed and will no doubt be found 
elsewhere in the Middle East. Earlier Middle East records of C. elongata (Elliott 
1955b ; i960) are now considered to be of kurdistanensis (see p. 44). 

Cymopolia barberae sp. nov. 

(PI. 8, fig. 2) 
Description. Units of 0-9 mm. external diameter (up to 1-22 mm. seen) internal 



44 CALCAREOUS ALGAE OF THE MIDDLE EAST 

diameter 43% of external, whorls showing n or 12 large near-spherical sporangia 
which occupy much of the wall-thickness, each sporangium associated with one very 
short primary branch and four secondaries. Diameter of the primary at the opening 
into the stem-cell 0-052 mm., sporangial diameter 0-130 mm., diameter of the outer 
expanded ends of the secondaries 0-055 mm - 

Horizon. Palaeocene-Lower Eocene of the Middle East. 

Holotype. The specimen figured in pi. 8, fig. 2, from the Kolosh Formation 
(Palaeocene-Lower Eocene) of Surdash, Sulemania Liwa, Iraq. V. 52057. 

Paratype. From the Sinjar Formation (Palaeocene-Lower Eocene) of Koi 
Sanjak, Erbil Liwa, Iraq. V. 52058. 

Other Material. Fragments in the Palaeocene Umm er Rhudhama Formation 
of Al Ghurra, Wagsa, Diwaniyah Liwa, S.W. Iraq. 

Remarks. This dainty little species is uncommon ; when compared with C. 
kurdistanensis the lesser number of proportionally larger sporangia gives its charac- 
teristic appearance. Although only known in thin section it is distinctive. Its 
relation to C. kurdistanensis may be compared with that of the larger C. rarifistulosa 
L. & J. Morellet to C. elongata. C. rarifistulosa, also known from fragmentary 
material only, from the Miocene of Saucats, France, is described as having very large 
subspherical sporangial cavities, apparently less than half the number seen in 
C. elongata. 

I have pleasure in dedicating this species to Mrs. Irene Barber, who has typed all 
my algal papers and reports. 

Cymopolia elongata (Defr.) Mun.-Chalm. 
(PI. 10, fig. 1) 

1955b Cymopolia cf. elongata (Defr.) ; Elliott : 126. 
i960 Cymopolia elongata (Defr.) ; Elliott : 225. 

Re-examination of the numerous specimens from the Iraqi and Arabian Palaeo- 
cene/Lower Eocene, formerly referred to C. elongata, has shown that many may be 
identified as near-vertical cuts tangential to the inner surface (stem-cell surface) of 
C. kurdistanensis, or as fragments of examples showing the terminally-widening 
secondaries of C. kurdistanensis. The remainder comprises random cuts of 
Cymopolia sp. which are more likely to be C. kurdistanensis from their associations. 

It is therefore concluded that the true C. elongata has not been met with in the 
Middle East collections studied, and that kurdistanensis is the typical and common 
Palaeocene and Eocene species of Cymopolia there, as elongata is in Europe. 

Cymopolia (Karreria) sp. 

(PI. 10, fig. 6) 

x 955t> Cymopolia {Karreria) sp. ; Elliott : 126. 

Description. Units of about 0-73 mm. external diameter and 0-39 mm. internal 



CALCAREOUS ALGAE OF THE MIDDLE EAST 45 

diameter, with whorls showing about 20 radially elongate, subpyriform sporangia of 
0-156 mm. by 0-090 mm. each communicating with the interior by a very short 
primary branch, which also divides into four secondaries. 

Horizon. Palaeocene-Lower Eocene of Iraqi Kurdistan. 

Material. Fragmentary thin-section material from the Kolosh Formation 
(Lower Eocene) of Surdash, and from the Sinjar Formation (Palaeocene-Lower 
Eocene) of Pila Spi, both Sulemania Liwa ; from probable Sinjar Formation, 
Sedelan, near Sulemania ; all localities in Iraqi Kurdistan. 

Remarks. This species is smaller than Cymopolia (Karreria) zitteli L. & J. 
Morellet from the Paris Basin Middle Eocene, shows fewer sporangia (20 against 24), 
and is proportionally thicker walled. By reason of the fragmentary nature of the 
material, the innermost layer of the wall, dividing the central stemcell from the 
cavities of the expanded primary branches, is usually missing. Although from the 
available evidence this is very probably a new species, it cannot be described as such 
from this material. 

Genus DACTYLOPORA Lamarck 1816 

1940 Dactylopora analolica Pfender : 237. 

1966b Dactylopora anatolica Pfender ; Massieux : 118, pi. 3, figs. 1-3. 

This large and handsome dasyclad, well-known from the Paris Basin Eocene, has 
not been met with in the collections studied by me, and the only Middle East record 
appears to be that of Pfender, quoted above, for the top Cretaceous (or possibly 
Palaeocene) of Turkey (Lutetian according to Massieux, but see p. 42 above). 

Genus DIPLOPORA Schafhautl 1863 

i960 Diplopora spp. Elliott : 219, 221. 

The richTriassic diplopore-limestones of central Europe and the Balkans are largely 
missing from the Middle East, at any rate from the areas studied by me. Although 
a thick development of marine Trias occurs in both Iraqi Kurdistan and Oman, 
original facies and subsequent dolomitization have combined to make these rocks 
almost completely barren of dasyclads. 

The Upper Triassic Elphinstone group in Peninsular Oman yielded two alleged 
dasyclads during thin-section studies by M. Chatton, one of which was recorded 
(Elliott i960) as Diplopora cf. phanerospora Pia. A re-examination of these speci- 
mens shows that they may not be dasyclads, and appear indeterminable. The 
evidence for R. G. S. Hudson's records of Diplopora as " not uncommon " and 
" occurs throughout " in different beds of the Asfal Formation of the Elphinstone 
Group (Hudson i960 : 304) is not known to me, as Hudson did not make these 
extensive collections available for the study of the algae. 

Diplopora sp. was also recorded (Elliott i960) from the north Iraqi Permian. 
Although species of the genus have been described from the Permian of Japan, 
Turkey (Giivenc 1965) and elsewhere, the Iraqi specimens appear on re-examination 
not to be diplopores. 



46 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Genus DISSOCLADELLA Pia 1936 

Diagnosis. Small tubular dasyclads, usually thin-wallecl with wide stem-cell 
cavity and often annular, each verticil showing horizontal branches with a short 
distally-swollen primary dividing into a bunch of short secondaries, usually four in 
number and terminally widening. 

Dissocladella deserta sp. now 

(PI. 10, figs. 7, 8) 

i960 Dissocladella sp. Elliott : 225. 

Description. Small hollow calcareous cylinder, straight-sided with rounded 
ends, length about 075 mm., external diameter 0-39-0-47 mm., internal diameter 
0-23-0-29 mm., verticils of about twelve branches each set 0-13 mm. apart vertically; 
branches showing a short primary, swollen to varying degree, and then dividing into 
four straight divergent secondaries which widen terminally to external pores. 

Horizon. Palaeocene and Eocene of the Middle East. 

Syntypes. The specimens figured in pi. 10, figs. 7, 8, from the Umm er Radhuma 
(Palaeocene-Lower Eocene) Formation of Wagsa and Aidah, Diwaniyah Liwa, S.W. 
Iraq. V. 52066, 67. 

Other Material. Very numerous random thin-sections from the same horizon 
and general area, and subsurface in the Basra oilfields, S. Iraq. Also from the 
Palaeocene Seiyan limestone of Wady Ghabar, Hadhramaut, S. Arabia. It may 
occur in the Lower Eocene of Egypt (see below). 

Remarks. This little Dissocladella, although very common, occurs in a porous 
microcrystalline dolomitic limestone and is always very poorly preserved, the 
structures showing as cavity-patterns amongst the pores and crystals. Although 
recognized some years ago, better material has not been found, and it is now 
described. It may well be the same as the " Dactylopora " sp. of Schwager (1883) 
from the Lower Eocene " Libyschen-Stufe " of Egypt, as remarked by Pia (1936b) ; 
the latter's comment on the relative sizes is an error. 

Dissocladella undulata (Raineri) Pia 
(PI. 11, figs. 4-6) 

1936a Dissocladella undulata (Raineri) var. ; Pia : 4, pi. 1. 

i960 Dissocladella undulata (Raineri) ; Elliott : 224. 

1966b Dissocladella undulata Raineri ; Massieux : 115, pi. 2, figs. 2, 3. 

Description (detail after Pia). Small hollow calcareous cylinder, length about 
1-4 mm., external diameter 0-24-0-32 mm., internal diameter 0-08-0-10 mm., with 
close-set verticils showing about 8 primary branches. These are narrow at the 
junction with the stem-cell and widen outwards, finally dividing into about six 
secondaries of similar shape which widen to the outer surface. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 47 

Horizon. Upper Cretaceous, North Africa, Western Mediterranean and Middle 
East. 

Material. From the subsurface Turonian of Musaiyib well, Hilla Liwa, Iraq ; 
also from the subsurface Turonian of Ras Sadr Well, Trucial Oman, Arabia. 

Remarks. This little alga was described by Pia from the Cenomanian-Turonian 
of Libya. In the Middle East, at the two localities given above, it is fragmentary 
and very poorly-preserved, but in both cases is associated with Trinocladus tripoli- 
tanus Raineri and the codiacid Boueina pygmaea Pia as at the type-locality ; the 
range of this little algal microflorule is therefore Upper Cretaceous. 

Dissocladella sp. 

Fragments of a small dasyclad showing branching of Dissocladella pattern have 
been noted in the north Iraq Maestrichtian, but are insufficient for description as a 
species. The occurrences are in the Tanjero Clastic Formation at Balambo (Sule- 
mania Liwa), in the Aqra/Hadiena Limestone of Chalki Islam (Mosul Liwa), and in 
the subsurface Formation of Makhul no. 1 well (Mosul Liwa). 

Dissocladella savitriae Pia 

(PI. 11, figs. 1-3) 

1936b Dissocladella savitriae Pia : 15, pi. 1, figs. 1-4, pi. 2, fig. 4, text-figs. 1-9. 
1955b Dissocladella savitriae Pia ; Elliott : 126, 128, pi. 1, fig. 2. 

Description. Thin-walled hollow calcareous cylinder, length of maximum 
fragment observed, 3-5 mm. ; (estimated length in life, up to 17 mm.), external 
diameter up to 17 mm., internal diameter from 69-78% of external in specimens 
measured, frequently about 71%. Successive verticils are represented by thin 
superimposed consecutive rings, of thickness up to 0-21 mm., feebly cemented 
together, which readily come apart and are themselves intrinsically fragile from their 
proportions. Rings are straight-sided within, convex without, giving the thallus an 
annular appearance externally. Each ring contains up to 44 globular or bluntly 
ovoid sporangial swellings of up to 0-13 mm. diameter : these are connected to the 
interior by a short primary canal of 0-026 mm. diameter and to the exterior by several 
bunched secondaries (4-6 from the type-description ; Middle East material does not 
conflict with this) . The secondaries are from the sporangial swelling itself, not from 
the primary ; they are about 0-013 mm. in diameter and they widen to emerge on 
the external surface as pores. 

Horizon. Palaeocene of Middle East ; " Danian " of India. 

Material. Solid specimens (broken tubes) and random thin-sections from 
numerous localities. In Iraqi Kurdistan, from the Sinjar Formation (Palaeocene- 
Lower Eocene) of Banik (Mosul Liwa), Kolosh Formation (Palaeocene-Lower Eocene) 
of Bekhme and of Rowanduz (Erbil Liwa), and of Surdash (Sulemania Liwa). 
Probably present (very poor preservation) in the Palaeocene limestones of the south- 
western desert, Iraq. In Arabia, from the subsurface Lower Eocene, Dukhan no. 3 



48 CALCAREOUS ALGAE OF THE MIDDLE EAST 

well, Qatar Peninsula ; from the Palaeocene of Jebel Faiyah, Trucial Oman ; and 
from the Palaeocene of the Batinah Coast, Oman. 

Remarks. This species was first described in great detail by Pia (1936b), his 
material coming from the Trichinopoly Danian, India (now regarded as Palaeocene). 
The Middle East material confirms his description, and also his reconstruction of the 
exterior, as all his material was in thin-section. His delightful reconstruction of the 
living algae in association with others [op. cit., fig. 43) appears reasonable from the 
extensive Middle East material studied. It should be noted that for algae at any 
rate, the Tethyan Palaeocene appears to commence immediately after the Maes- 
trichtian, the flora (including D. savitriae) extending up into the Lower Eocene ; 
this point is discussed in more detail later in this work. 

Genus EOGONIOLINA Endo 

1953a Eogoniolina johnsoni Endo : 97-104, pi. 9, figs. 5-10. 
i960 Engoniolina johnsoni Endo [lapsus calami) ; Elliott : 219. 

Remarks. As described by Endo, the Permian Eogoniolina was a club-shaped 
dasyclad with a lower, long cylindrical stem-like portion which extended up to a 
terminal expanded globular portion : this is well-shown in his reconstruction {op. 
cit., text-fig. p. 102). His microphotographs, however, in this and later papers, 
usually show the pear-shaped or pyriform terminal portion only, and it was by 
comparison with this that the species was recognized in the Iraqi Permian by me. 
Subsequent re-study of this material shows that these specimens are in fact pyriform 
segments of Mizzia velebitana. At both the Iraqi and Japanese localities normal 
spherical examples of this common species are abundant. Without prejudice to 
Endo's interpretation of his original Japanese material, the Iraqi record is therefore 
withdrawn. Eogoniolina pamiri has been described from the Turkish Permian 
(Giivenc 1966b). 

Genus EPIMASTOPORA Pia 1923 

Diagnosis (emend, after Endo). Similar to Pseudoepimastopora, but with rela- 
tively long pores having the same width throughout their length. 

" Epimastopora minima Elliott " (= Tauridium sp.) 

1956 Epimastopora minima Elliott : 327, pi. 1, figs. 1, 3. 

This species was founded on fragmentary remains which occur abundantly in 
samples from at or near the base of the Satina Formation, or the middle evaporitic 
unit of the Chia Zairi or Iraqi Permian. The original remains are almost comminu- 
ted, and a re-examination in the light of subsequent studies on Epimastopora and 
Pseudoepimastopora suggested that the original generic allocation is doubtful. The 
description of the codiacid genus Tauridium (Guvenc 1966a) shows clearly that the 
Iraqi fossils are debris of a species of this genus, and not remains of a dasyclad. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 49 

Epimastopora sp. 

Fragmentary remains referred to the genus are said by Rezak (1959) to be 
abundant in the upper part of the Permian Khuff Formation (probably Upper 
Permian) of Dammam no. 43 well, Saudi Arabia. 

Genus FURCOPORELLA Pia 1918 

Diagnosis. Cylindrical dasyclad tube with successive verticils of horizontal 
paired straight radially divergent branches ; each pair of branches commences at a 
single opening on the interior : bifurcation occurs almost at once and the two 
divergent secondaries extend to the exterior. 

Furcoporella diplopora Pia 

(PI. 11, figs. 7-9) 

1918 Furcoporella diplopora Pia : 209, pi. 1, figs. 1, 2 ; text-fig. 46. 

1940 Furcoporella diplopora Pia ; Pfender : 242. 

1956 Furcoporella diplopora Pia ; Elliott : 332, pi. 2, figs. 5, 6. 

1960 Furcoporella diplopora Pia ; Elliott : 225. 

1966 Furcoporella diplopora Pia ; Massieux : 121, fig. 4, pi. 4, figs. 8, 9. 

Description. Hollow cylindrical calcareous tube, long and straight-sided ; 
length (incomplete) up to 5-0 mm. seen, with external diameter of up to o-6 mm., 
and corresponding internal diameter of 0-325 mm. ; d/D ratio on smaller specimens 
from 48-55%. Numerous regular horizontally-set verticils of paired branches ; 
about n per mm. of tube-length. Each verticil shows about 8 pairs, each commenc- 
ing on the inside of the tube as a single large pore : in transverse section the very 
short primary canal is seen to divide at once into two secondaries, which diverge at 
an obtuse angle varying from 45-70 ° and proceed, widening slightly, in a straight 
course to the periphery where they widen sharply to emerge as external pores. In 
vertical section only a succession of straight, coarse, waisted pores is seen ; in an 
oblique vertical cut the plane of section, traversing successive near-identical pore- 
pairs outwards, shows that the canals widen transversely but not vertically before 
splitting into two. 

Horizon. Middle Eocene of Central and Southern Europe : Palaeocene and 
Eocene of Middle East. 

Material. In Iraqi Kurdistan, from the Sinjar Formation (Palaeocene-Lower 
Eocene) of Banik and (subsurface) Gullar no. 1 well (both Mosul Liwa) and Kashti 
(Sulemania Liwa) ; from the Kolosh Formation (Palaeocene-Lower Eocene) of 
Rowanduz and Koi Sanjak (both Erbil Liwa), and of Sedelan (Sulemania Liwa). In 
southern Iraq, fragmentary and ill-preserved remains from the Palaeocene Ghurra 
Beds of the Umm er Rhudhama Formation, Wagsa (Diwaniyeh Liwa) and elsewhere 
in the southwestern Iraqi desert. In Arabia, from the Palaeocene-Lower Eocene of 
the Batinah Coast, Oman ; from the Palaeocene of Jol Ba Hawar, and the Palaeo- 
cene-Lower Eocene of Aqabar Khemer, Hajar, both Hadhramaut. See also 
Hadhramaut record of Beydoun (i960 : 146). 



50 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Remarks. Pia's type-material was from the Austrian Middle Eocene ; the 
species also occurs in the Middle Eocene of Egypt and Syria (Pfender 1940), Iraq 
(Sulemania district), and South Oman (Jebel Tanamir). The Middle Eastern 
Palaeocene-Lower Eocene examples listed above correspond in structure to the type 
material, but reach a larger size in many if not all examples. External diameters 
quoted by Pia and Pfender, for example, are 0-26-0-34 mm. and 0-35-0-45 mm 
respectively, whilst the older Iraqi material described above may attain a corres- 
ponding dimension of 0-6 mm. 

Although F. diplopora is represented fossil by stout calcareous tubes, the structures 
preserved afford but an imperfect record of those of the living plant. The larger 
examples are no better than the smaller in this respect. All indicate a very short 
primary branch and two secondaries : presumably these latter, which are seen to 
expand as they reach the outer edge of the zone of calcification, branched further into 
a spray of uncalcified tertiary branchlets : there is no evidence at all of the sporangia. 
The relationships of the genus remain doubtful. 

Genus GRIPHOPORELLA Pia 1915 

Diagnosis. Very thin-walled cylindrical, club or ovoid shaped dasyclad calcifi- 
cations, with numerous simple perforations ; so thin-walled that the perforation- 
structures are insufficient for elucidation of the branch-structure. 

Remarks. Griphoporella is an inclusive name for those dasyclads whose calcifica- 
tion was confined to a thin hood-like sheet which affords no clue to the detailed 
branch-structure, size of stem-cell, etc. of the original plant. The species referred 
to it range from Triassic to Palaeocene and may be quite unrelated phylogenetically ; 
see especially under G. arabica below. 

Griphoporella cf. perjoratissima Carozzi 

(PI. 12, fig. 4) 

I 955t > Griphoporella perjoratissima Carozzi : 203, text-fig. ia-d. 
i960 Griphoporella perjoratissima Carozzi ; Elliott : 223. 

Description. See under remarks. 

Horizon. Top Jurassic and bottom Cretaceous of Europe and Middle East. 

Material. Fragments from the subsurface Upper Jurassic Najmah Formation 
of Kirkuk Well no. 117, Iraq ; in Arabia, from top Jurassic and bottom Cretaceous 
levels at Haushi, Southern Oman, and from the Lower Cretaceous of Burun, Wady 
Hiru Basin, Hadhramaut. 

Remarks. The material listed above is extremely fragmentary, but is of a thin- 
walled dasyclad, circular in cross-section, and showing very many simple pores. It 
is similar in age-occurrence to Carozzi's G. perjoratissima (Portlandian-Berriasian) , 
and has a similar appearance in random cut to the type-figures (Carozzi 1955b, fig. 
ia). The pores are 0-030-0-040 mm. in diameter, and about 0-020 mm. apart. This 
is larger than in G. perjoratissima (0-015-0-019 mm. diameter set 0-009-0-012 apart), 



CALCAREOUS ALGAE OF THE MIDDLE EAST 51 

and would give a pore-count per square millimetre of about one third that quoted 
for the type. It is however closest to this rather than to the other Upper Jurassic 
species G. undulata Pia, G. irregularis Pia and G. ehrenbergi Bachmeyer (comparison- 
table of Carozzi, op. cit., : 206). In view of this correspondence, and of the in- 
adequacy of the Middle East material for full description, it is given the qualified 
determination above. 

" Griphoporella arabica Pfender 1938 " 
(Ovulites maillolensis Massieux) 

(PI. 12, figs. 1, 3) 

1938 Griphoporella arabica Pfender : 69, pi. 9, figs. 5-8. 

1940 Griphoporella arabica Pfender ; Pfender : 241. 

1955b Griphoporella arabica Pfender ; Elliott : 126. 

1966a Ovulites maillolensis Massieux ; Massieux : 241, pis. 1, 2. 

Description. Broadly club-shaped or elongate-ovoid, thin-walled, hollow calci- 
fication, external diameter up to 0-9 mm., length not known but at least three times 
diameter from oblique-longitudinal sections. Wall thickness up to 0-078 mm., 
perforated by close-set straight-sided pores of about 0-013 mrn - diameter, widening 
very slightly at the external surface, and set 0-006-0-013 mm. apart as seen in section. 

Horizon. Paleocene and Eocene of France, North Africa and Middle East. 

Material. In Iraqi Kurdistan, from the Kolosh Formation of Koi Sanjak (Erbil 
Liwa) and from the Sinjar Formation of Sirwan (Sulemania Liwa), both Palaeocene- 
Lower Eocene. In Arabia, from the Palaeocene-Lower Eocene of Sahil Maleh, 
Batinah Coast, Oman, and from the Seyun Limestone development of the Umm er 
Rhudhama Formation (Palaeocene) of Ma'adi Pass, east of the Mukulla-Shihr road, 
Hadhramaut. 

Remarks. The species was described by Pfender from the Lower Eocene of 
Morocco, and recorded by her from the Middle Eocene of Egypt and Syria ; a 
related species was mentioned from Madagascar. Pfender's specimens were smaller, 
with external diameters of up to 0-4-0-58 mm., and thinner- walled (0-040-0-050 mm. 
wall-thickness) , but the pores and pore-spacing were similar, and it seems unnecessary 
to refer the Middle East specimens to a new species because some individuals attain 
a larger size. 

In her type-description of the French Lower Eocene codiacean Ovulites maillolensis 
Massieux (1966a) records that from preliminary studies on thin-sections she deter- 
mined this species as Griphoporella arabica Pfender. Further studies on whole 
(isolated) segments or articles, and comparison with the classic and beautifully- 
preserved Paris Basin species (Munier-Chalmas 1881) convinced her that these 
fossils were remains of Ovulites, as was also Pfender's North African material. The 
new species was created as Pfender's type-material could not be traced and the 
original description was inadequate in view of the new evidence available. 

I agree with Mile. Massieux's conclusions. The Middle Eastern material described 
above was identified by comparison with Pfender's accounts (1938 : 1940), and is 



52 CALCAREOUS ALGAE OF THE MIDDLE EAST 

well-known in the literature as G. arabica. It shows no diagnostic dasyclad charac- 
ters to refute the new allocation (and indeed the genus Griphoporella itself is a 
receptacle for various inconclusive dasyclads, probably not closely related). The 
description of this codiacean is retained here for comparison with dasyclads as, 
unlike the problematic Thaumatoporella, it is well-known in dasyclad literature. 

Genus GYROPORELLA Giimbel 1872 

i960 Gyroporella cf. maxima Pia ; Elliott : 219. 

Many Permian species of Gyroporella have been described from Japan, also one 
from the U.S.A. (Johnson 1963), and one from Turkey {Gyroporella sp., Bilgiitay 
1959). My record of G. cf. maxima from Iraqi Kurdistan was based on a single 
random section : no further material has been found to substantiate this, and the 
determination is therefore abandoned. 

Genus INDOPOLIA Pia 1936 

Diagnosis. Calcareous tubular dasycladacean showing verticils of branches each 
of which consists of one primary dividing into two secondaries set one above the 
other (vertically) : in fertile whorls each branch gives rise to two sporangia. 

Indopolia satyavanti Pia 

(PI. 12, fig. 2) 

1936 Indopolia satyavanti Pia : 20, pi. 1, figs. I, 5-13, text-figs. 17-19. 

Description (details after Pia). Hollow calcareous elongate tubes, length 
unknown but perhaps 5-0 mm. or more ; external diameter (fertile part) o-86-i-i6 
mm., with internal diameter of 44-49% external ; (sterile part) 0-55-0-98 mm. 
external, internal 47-55%. Fertile whorls of perhaps 28 branches ; each branch 
consists of one primary, which is set obliquely at 60-70 ° from the horizontal : this 
divides into two secondaries set nearly horizontally one above the other and reaching 
the outer surface almost horizontally i.e. nearly at right angles to it. The second- 
aries increase in diameter to become funnel-shaped and almost in contact at the 
external surface, and occasion a polygonal pattern there. Two small pyriform 
sporangia (diameter 0-09-0-12 mm.) are attached at or near the branch-junctions. 
The sterile whorls do not of course show sporangia, but the branches are similar. 

Horizon. " Danian " of India ; Palaeocene of Middle East. 

Material. In Iraqi Kurdistan, from the Sinjar Formation (Palaeocene-Lower 
Eocene) of Banik, Mosul Liwa, where it is uncommon. Possibly also in Arabia, from 
the Upper Palaeocene of the Batinah Coast, Oman (poorly preserved). 

Remarks. Pia's material was from the Trichinopoly Danian of India, where the 
species was abundant and described as the " almost constant companion of Disso- 
cladella savitriae " . In the Middle East, although D. savitriae is widespread, and 



CALCAREOUS ALGAE OF THE MIDDLE EAST 53 

with it the non-dasyclad alga Parachaetetes asvapatii Pia, also described from the 
same Indian locality, Indopolia is very rare. In Kurdistan it was found in the 
present investigation only at Banik, and there is possibly one other record from 
Oman (see above). 

The Banik material shows sterile whorls only. A measured example has an 
external diameter of 0-455 mm., and internal diameter of 0-221 mm., or 49% ; 
although a little smaller, the section is closely similar to that of a sterile specimen 
figured from the type-material (Pia 1936b, pi. 1, fig. 11). 

Although the algal sampling for the present study was far from exhaustive, the 
poor showing of Indopolia in the Middle East, when compared with its Indian 
associates Dissocladella and Parachaetetes is probably significant. The rare occur- 
rence, of sterile remains only so far, suggests that it did not manage to spread 
westwards along Tethyan coasts. Indopolia feddeni Rao & Vimal (1955) is uncom- 
mon in the Palaeocene of Pakistan. Perhaps I. satyavanti is replaced in the algal 
economy by the prolific Cymopolia kurdistanensis, not known from the Trichinopoly 
beds. 

Genus LARVARIA Defrance 1822 

i960 Larvaria sp. Elliott : 223. 

The writer's i960 record of Larvaria sp. from the Kurdistan Maestrichtian, is 
based on a worn example of Cymopolia tibetica Morellet (see above, under C. tibetica). 
Larvaria sp. was recorded by Barthoux (1920) from the Lower Eocene of Suez, Egypt. 



Genus MACROPORELLA Pia 1912 
i960 Macroporella sp. Elliott : 219, 221. 

My i960 records of this genus, from the Permian of Iraqi Kurdistan and from the 
subsurface Upper Triassic of Qalian no. 1 well, Mosul Liwa, Iraq, were made on 
scarce and poorly-preserved material. No further specimens of either have been 
found. The Permian record is now discounted, and the Triassic one remains very 
doubtful. 

Jurassic and Cretaceous species formerly referred to this genus are now described 
under Pianella and Acroporella. 

Genus MORELLETPORA Varma 1950 

1950 Morelletpora nammalensis Varma : 207, figs. 1, 2. 

1955 Morelletpora nammelensis Varma ; Varma : ioi-iii, 2 pis. 

i960 ? Morelletpora nammelensis Varma ; Elliott : 225. 

My i960 record of this species (a queried determination) from the Palaeocene- 
Lower Eocene of Iraq, based on a random section, proves to be from material of 
Middle Eocene age and is not further dealt with here. 



54 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Genus MIZZIA Schubert 1907 

1907 Mizzia Schubert : 212. 

1908 Mizzia velebitana Schubert : 382, pi. 16, figs. 8-12. 
1920 Mizzia Schubert ; Pia : 18. 

1942 Mizzia Schubert ; Johnson and Dorr : 63. 
1959b Mizzia Schubert (emend) ; Rezak : 534. 

Diagnosis (after Rezak). " The thallus is composed of segments joined end to 
end in a loosely articulated fashion. The segments are generally disaggregated and 
are rarely found joined together like a string of beads. Individual segments are 
spheroidal to cylindroidal or pyriform and are composed of a central cavity 
(generally barrel-shaped) through which the stipe extended. Radiating from the 
central cavity are simple expanding, unbranched rays arranged in regular, alternating 
horizontal rows. At the periphery of the segment the expanded rays are in mutual 
contact. The alternating nature of the rays and their crowding at the periphery 
gives rise to a hexagonal (honeycomb) pattern on the surface of each segment. 
Species are based on shapes and dimensions of the segments and their internal 
structures ". 

Mizzia velebitana Schubert 1908 

(Pis. 13, 14) 

1908 Mizzia velebitana Schubert : 382, pi. 16, figs. 8-12, text-fig. 5. 

1933 Mizzia velebitana Schubert ; Kiihn : 155. 

1955a Mizzia velebitana Schubert ; Elliott : 83. 

1959b Mizzia velebitana (Schubert) emend. Rezak ; Rezak : 536, pi. 72, figs. 1-3, 5, 6, 8-10, 

12, 13, 15-19. 

1959 Mizzia velebitana Schubert ; Bilgutay : 49, pi. 1, figs. 2-3, pi. 2, fig. 1. 

i960 Mizzia velebitana Schubert ; Elliott : 219. 

Description (from Iraqi material). Hollow, calcareous, bead-like segments, 
spheroidal, ovoid or elongate-ovoid, pear-shaped or pyriform ; length up to 2-0 mm., 
external diameter (maximum) up to 2-25 mm., internal diameter measured in the 
same transverse plane, 60-70% of external ; polar (proximal and distal) openings or 
gaps in the segment, from 0-18-0-36 mm. diameter in a large segment. Wall 
perforated by about 12 successive horizontal verticils of coarse pores (short branches), 
usually 20-25 per verticil over all but the polar ends of the segment. The pores of 
each verticil are set alternately to those of adjacent verticils, to give the external 
and surface-tangential section appearance of a large closely-set hexagonal mesh. In 
vertical section the branches are seen to be wedge-shaped, widening slowly from 
interior to exterior, and usually of about 0-18 mm. diameter in large examples. 
Externally the pores may be open or closed : in the latter case they are roofed by a 
thin externally-convex projecting calcareous covering. 

Horizon. Permian ; North America, North Africa, Europe, Asia. 

Material. In Iraq, common throughout most of the thickness of the Zinnar 
Formation and the Darari Formation, and occurring rarely in the intermediate 
Satina Evaporite Formation ; that is, probably from within the upper part of the 
Lower Permian to near the top of the Upper Permian (but see under Stratigraphic 



CALCAREOUS ALGAE OF THE MIDDLE EAST 55 

Ranges) : abundant over this range in much of the material from the sampled 
surface sections of Ora and Harur, Mosul Liwa, and also from subsurface Upper 
Permian in Atshan no. 1 well, in the south of Mosul Liwa (see Hudson 1958 ; 
Dunnington, Wetzel & Morton 1959). Elsewhere in the Middle East Permian 
recorded by Kuhn (1933) from Iran, by Bilgiitay (1959) and Giivenc (1965) from 
Turkey and by Rezak (1959b) from Saudi Arabia. 

Remarks. Mizzia velebitana is a characteristic Permian microfossil of circum- 
global distribution : central and southeastern Europe and north Africa, the Middle 
East, Sumatra and Japan, and the southwestern United States. Its distribution 
was plotted and compared by Pia (1937) with that of the living warm-water codiacid 
alga Halimeda tuna Lmx. Extensive bibliographies of these occurrences have been 
given by Pia (1937), Johnson & Dorr (1942) and Rezak (1959b) : that given above 
refers mostly to the Middle East occurrencies. 

Rezak {op. cit.) has discussed the genus and type-species in detail, and given 
revised diagnoses for them. That for the genus is quoted above in full : the 
description given here is based on the material from Iraqi Kurdistan studied by 
me. When compared with the equivalent species-diagnosis of Rezak, which was 
a synthesis of previous records and his own study of Saudi Arabian material, it is 
seen that the Iraqi specimens do not attain the maximum size (length breadth and 
pore-diameter) quoted for the species elsewhere, but are larger in size and equal in 
pore-diameter to the Saudi Arabian specimens. 

Rezak transferred Mizzia to the dasyclad tribe Diploporeae, after clear demonstra- 
tion of the regular arrangement of the side-branches : I agree with this. All 
previous workers have followed Schubert (1908 : 383) in supposing the stem-cell in 
each globular Mu^'a-segment to have filled the central cavity, so that the primitive 
unbranched side-branches commenced approximately where the inner calcareous 
wall is seen in the fossil (e.g. Pia 1920 : 21 ; Rezak 1959 : 534). Theoretically it is 
possible that a thinner central stem-cell gave rise to thin radiating branches which 
thickened terminally and were calcified only around the thicker peripheral portions : 
a comparable arrangement exists in the Recent Bornetella. Although this is a much 
more complex dasyclad than the Permian Mizzia is believed to have been, it was the 
comparison-genus used by Wood (1943) in reconstructing the non-calcified parts of 
the still older dasyclad Koninckopora from the Carboniferous. However, the serial 
arrangement of connected Mizzia-segments (a phenomenon known from occasional 
short strings of consecutive fossil segments from various localities, though not yet 
from Iraq) is believed to indicate a jointed plant somewhat like the living Cymopolia 
(Pia 1920 ; Rezak 1959b). Mechanically, the 5om£te//fl-interpretation would result 
in segments which would probably be extremely fragile for the assumed mode of life 
of Mizzia, even in quiet waters : Bornetella itself is a single non-segmented dasyclad, 
attached by a short holdfast. It therefore seems more likely, though not definitely 
known, that the older interpretation is correct. Taken in conjunction with the 
abundance of the fossil segments and their wide distribution, this would make 
Mizzia a common dasyclad of primitive structure, vigorous growth, and thick juicy 
stem-cell. This is consistent with the picture set out in the section on ecology. 



56 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Several species, other than the type-species, have been described for Mizzia : e.g. 
M. yabei Karpinsky, M. japonica Karpinsky, M. minuta Johnson and Dorr, M. 
bramkampi Rezak, M. cornuta Kochansky and Herak. These are based primarily on 
differences in segment shape and size, and sometimes on branch-structure. Morpho- 
logically such species are recognizable taxonomic entities. However, usually they 
seem to be associated with M. velebitana, and, so far as one can tell from the litera- 
ture, to be also a minority of the local Mmza-populations. Bearing in mind the 
variation of segments within a plant, and the environmental local variations in plant- 
populations, as evidenced by the study of Hillis (1959) on Recent Halimeda, the 
genus with which Pia compared Mizzia for distribution, it is felt that mostly they 
may well be, in the botanical sense, of varietal status at best. M. bramkampi Rezak, 
with its distinctive funnel-shaped branch-structure, appears the one most likely to be 
a distinct local species. This was described from Saudi Arabia (Khuff formation ; 
probably Upper Permian) : other species recorded from the Middle East are Mizzia 
yabei and M. minuta from Turkey (Bilgiitay 1959) ; also M. tauridiana (Guvenc 

1965). 

All the Iraqi Kurdistan specimens seen are referred here to M. velebitana. Occa- 
sional specimens resembling M. yabei are considered atypical segments of the type- 
species. One or two specimens resemble some of Endo's figured Eogoniolina, but 
not his reconstruction, and there is no associated evidence to show that these are 
other than M. velebitana. Also in the Iraqi material are various specimens corres- 
ponding to M. cornuta Kochansky & Herak (i960), a species in which the external 
bulging terminations of the branches (or pores) are roofed over by a thin projecting 
convex calcareous covering. Setting aside worn material, and many fossil Mizzia 
segments are recognizably abraded, it would seem that in apparently well-preserved 
material the pores can be open or closed. This point was discussed in some detail by 
Pia (1920), who suggested that this difference in the otherwise homogeneous 
assemblage of segments might possibly be due to the covered pores having contained 
sporangia. He also drew attention to the effect of light-intensity, varied by shading 
due to stones, etc. on the calcification of living algae, and to the differences in the 
calcification of the older and younger segments of the same plant. I believe that in 
the case of Mizzia light intensity may have influenced this calcification ; in view of 
what is known of this phenomenon in modern algae, and the random distribution of 
specimens with roofed pores in Mizzia, the character does not seem worthy of 
occasioning a distinct specific name. It is true that Kochansky & Herak {op. cit., 
text-fig. 7) give a longer range for M. cornuta than for M. velebitana in the Jugoslav 
Permian, but in Iraq at any rate M. cornuta is represented by a small minority of 
specimens within the main range of M. velebitana. 

Genus MUNIERIA Deecke 1883 

Diagnosis. Dasyclad with thin central stem-cell giving rise to regularly and 
widely spaced verticils of thin straight horizontal radial side-branches, the whole 
thickly calcified to give a rigid structure of centrally fused calcified successive 
whorls. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 57 

Munieria baconica Deecke 
(PI. 15, figs. 3-8) 

1883 Munieria baconica Deecke : 9, pi. 1, figs. 4-8. 

1920 Munieria baconica Hantk. ; Pia : 144, pi. 7, figs. 16-26, text-fig. 25. 

1948 Munieria baconica Hantk. ; Carozzi : 351, pi. 6, fig. 3, text-fig. 48. 

1955b Munieria baconica Deecke ; Elliott : 126. 

1955a Munieria baconica Deecke ; Carozzi : 47, text-figs. 10-12. 

1958a Munieria baconica Deecke ; Elliott : 255, pi. 45, fig. 4. 

1958 Munieria baconica Deecke ; Radoicid : 79, pi. 1, text-figs. 2, 3. 

i960 Munieria baconica Deecke ; Elliott : 223, 224. 

1962 Munieria baconica Hantken ; Delmas & Deloffre : 216, pi. 3. 

Description (based on Pia and Carozzi). Dasyclad with external diameter (at 
verticil-level) of o-6-i-6 mm., internal diameter (stem-cell) of 0-05-0-26 mm. ; 
verticils set apart at distances of about 66% of their diameter. Each verticil 
horizontal, consisting of about 16 straight radial simple branches of about 0-08-0-09 
mm. median diameter. Verticils and stem-cell thickly calcified, to give successive 
thick horizontal discs at verticil level, joined to the thick stem-cell calcification. 
Occasionally calcification unites the discs peripherally. 

Horizon. Upper Jurassic-bottom Cretaceous of Switzerland and Jura ; top 
Albian of France (Delmas & Deloffre 1962) ; Upper Jurassic-Lower Cretaceous of 
Italy (Sartoni and Crescenti 1962). Lower Cretaceous of Spain, central and south- 
eastern Europe and Middle East. 

Material. In the Middle East, probably common but always fragmentary. 
Seen in the Lower Cretaceous of Iraqi Kurdistan, Barremian to Aptian : Sarmord 
Formation, Barremian level, and Qamchuqa Formation, Albian level of Surdash 
(Sulemania Liwa) ; Qamchuqa Formation of Ru Kuchuk and Rowanduz, Mosul 
and Erbil Liwas and Zibar-Isumeran, Mosul Liwa ; Aptian, Albian and Barremian- 
Aptian levels respectively. In southern Arabia, Lower Cretaceous of Hadhramaut 
(e.g. Mintaq, Wady Hajar ; Barremian-Aptian) , and Lower Cretaceous of Oman 
(e.g. Haushi, South Oman). 

Remarks. Originally described by Deecke (1883) from the Aptian of Hungary. 
Later Pia (1920) attempted a reconstruction of this alga from thin-section material. 
Carozzi (1948 ; 1955a), gave line drawings of random sections of Swiss material : 
he recorded it from Upper Kimmeridgian to Valanginian. Radoicic (1958) gave 
excellent photographs of random sections of Jugoslav material from the Valanginian- 
Hauterivian. 

My Middle East records (Elliott 1955b ; 1958a ; i960) record the species from 
Barremian to Albian. 

This Middle East material is extremely fragmentary. It occurs in the Lower 
Cretaceous " debris-facies " (Elliott 1958a), an off-shore deposit in which small 
calcareous scraps, largely algal, form an appreciable part of the sediment. Much of 
this debris is unidentifiable, but Permocalculus spp., Actinoporella podolica, and 
Salpingoporella arabica can be recognized : their study was greatly facilitated by the 
occasional discovery of whole or near-complete segments, verticils or individual 



58 CALCAREOUS ALGAE OF THE MIDDLE EAST 

thalli. Munieria is the most fragmentary of all : it survives as little looped or 
hooked scraps. These have been identified by reference to the figured random cuts 
of debris of Carozzi (1955a), supplemented by the figures of Radoicic (1959), rather 
than by comparison with Pia's topotype material (1920). Since the calcification of 
Munieria is proportionally heavier than that of the comparable Adinoporella, it is 
reasonable to suppose that in life it was more porous and hence more fragile when the 
skeleton was dismembered. 

It seems not unlikely that the combined records of the various European and 
Middle East occurrences, Kimmeridgian to Albian, embrace more than one species: 
differences in average size and proportions, number of branches per verticil, etc. are 
suggested by the random thin-sections of various authors (e.g. compare the figures of 
Radoicic 1958 with those of Delmas & Deloffre 1962). Such a revision would have 
to be made on much better material than has been available for the present study : 
the Middle Eastern debris, therefore, is here referred to M. baconica, the only 
described species. The alleged figure of a complete verticil of a Middle East 
Munieria (Elliott 1958a, pi. 48, fig. 1) is an error. 

Genus NEOMERIS Lamouroux 1816 

Diagnosis. Calcified tubular dasyclads showing successive verticils of branches 
in which each primary branch divides into a stalked sporangium and two secondary 
sterile branches set in the same plane : the calcification surrounds the sporangia and 
secondaries, but not the primaries, which are weakly calcified or uncalcified. 

Neomeris cretacea Steinmann 
(PI. 15, figs. 1, 2) 

1899 Neomeris (Herouvalina) cretacea Steinmann : 149, text-figs. 14-18. 
1955 Neomeris cretacea Steinmann ; Elliott : 126, pi. 1, fig. 7. 
i960 Neomeris cretacea Steinmann ; Elliott : 223. 

Description (from Middle East material). Slightly irregular tubular calcified 
dasyclad of 1-10-1-25 external diameter, internal diameter 41-48% external, length 
(incomplete) seen to 6 mm. ; walls showing close-set verticils of neomerid groupings 
of sterile branches of about 0-050 mm. diameter and ovoid sporangia of 0-180 mm. 
length and 0-090 mm. diameter. 

Horizon. Upper Cretaceous of Mexico, Iraq and possibly from circum-Medi- 
terranean ; top Albian of France (Delmas & Deloffre 1962). 

Material. Two good sections only ; from the Bekhme Formation (Maestrich- 
tian) of Chia Gara, and from the Aqra/Bekhme Limestone development (Campanian- 
Maestrichtian) of Gal-i-Mazurka at Amadia ; both localities in Mosul Liwa, Iraq. 
Numerous random thin-sections, completely or near-completely recrystallized, 
possibly of the same species, possibly of other species of this genus, occur in the 
Upper Cretaceous Limestones of Iraqi Kurdistan. 

Remarks. Steinmann's species was described from the Cenomanian of Mexico 
(Steinmann 1899). His specimens showed a larger size than the Iraqi material : 



CALCAREOUS ALGAE OF THE MIDDLE EAST 59 

up to 2 mm. external diameter and an estimated length of 10 mm. Some of the 
indeterminable recrystallized Iraqi specimens reach this diameter. Dimensions of 
branches and sporangia are comparable in the two occurrences. Fragmentary 
Cretaceous material referred to the genus Neomeris has been described or recorded 
from the Danian of Morocco (Pia 1932), Cenomanian of Libya (Pia 1936a), Upper 
Cretaceous of Morocco (Pfender 1938) and Cenomanian-Turonian of Spain and 
Southern France (Pfender 1940). See also Massieux (1966b : 115, fig. 1). 

Although the Iraqi evidence is very limited, it seems reasonable, in view of the 
measurements taken, especially of the sporangia, to refer the specimens to Stein- 
mann's species. There is a resemblance between PI. 14, fig. 2 of the present work and 
Steinmann's text-fig. 15, corresponding apparently to similar orientation of section 
and to individuals of similar development. If published dimensions and measure- 
ments on illustrations are combined, the Iraqi specimens are seen to be thicker- 
walled (d/D 41-48%) than the type-material (d/D 48-60%), but this is closer than the 
very thin-walled French Albian specimens (d/D 62-78%) of Delmas & Deloffre 
(1962), which should probably be referred to a new species, and which compare in 
this respect with the Lower Cretaceous N. pfenderae Konishi and Epis (1962). The 
difficulties of comparing species based on different kinds of fossil evidence (whole or 
fragmentary, few or numerous well-preserved specimens, etc.) are especially marked 
with Cretaceous Neomeris. It may be that further material would show the Iraqi 
form, which is Senonian-Maestrichtian, to be a different species from the type which 
is Cenomanian-Turonian, but it is closer to it than are the older species. 

Genus PAGODAPORELLA Elliott 1956 

Diagnosis. Small calcified tubular dasyclad showing externally vertical rows of 
slightly alternating large pores with small interpore portions, the pores widening 
sharply from within outwards. 

Pagodaporella wetzeli Elliott 
(PI. 17, figs. 9, 10) 
1956 Pagodaporella wetzeli Elliott : 333, pi. 2, figs. 3, 4. 

Description. Small tubular calcified dasyclad ; observed length (incomplete) 
1 mm., external diameter about 0-34 mm., internal diameter 58-66% of external, 
octagonal in cross-section. Successive verticils of about eight branches each, 11-14 
verticils per mm. of tube-length ; branches represented by large pores, externally 
roughly hexagonal and separated only by narrow interstices of calcareous wall- 
material : internal pore-diameter 0-040-0-050 mm., widening sharply to an extrenal 
diameter of 0-065-0-090 mm., so that in vertical section the wall-material shows as 
small well-spaced triangles or wedges, the apices outward. Externally the large 
window-like pores give an appearance of slightly irregular vertical rows. 

Horizon. Palaeocene-Lower Eocene of Iraqi Kurdistan. 

Material. Solid and thin-section specimens from the Kolosh Formation 



6o 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



(Palaeocene) of Bekhme, Erbil Liwa ; thin-section material from the Sinjar Forma- 
tion (Palaeocene-Lower Eocene) of Banik, Mosul Liwa, and from the Kolosh Forma- 
tion (Palaeocene-Lower Eocene) of Sedelan, Sulemania Liwa ; all in northern Iraq. 

Remarks. Pagodaporella is the fossil record of a little, thick- branched dasyclad 
which calcified only near the stem-cell, at the base of the branches, no traces being 
left of branch-structure nor of sporangia : its relationships are therefore uncertain. 
The peculiar thin-section appearance, with more gaps than skeleton, was known for 
some time before the discovery of solid specimens, which when sectioned led to the 
elucidation of the random sections. 

The living Dasycladus (D. clavaeformis (Roth) Ag. ; Mediterranean) shows a 
comparable limited calcification which is however not identical. Here each verticil 
shows 10-15 branches, branched outwardly to the third degree and also bearing 
sporangia : the primaries narrow markedly at their inner junctions with the stem- 
cell, and between their points of insertion the fleshy stem-cell wall is markedly 
thickened inwardly, within the stem-cell itself, and thinly calcified externally. 





Fig. 4. Diagrammatic transverse sections of Dasycladus (above) and Pagodaporella (below, 
hypothetical). Greatly enlarged, X 150 approx. Spaced stipple, plant tissue ; close 
stipple, thickened portions of stem-cell wall ; black, calcareous structure. Each 
section shows half the stem-cell with branches attached. The reconstruction for 
Pagodaporella explains the possible origin of the structure found fossil. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 61 

(Fritsch 1935 : 388). If fossilized this structure would give a very thin cylindrical 
test perforated by alternating pores. If however calcification were to develop 
further outwards between the swelling primaries, wedge-shaped interstices would 
develop, but much closer than in Pagodaporella. Since dasyclad branches are norm- 
ally thin at the points of origin and then swell out, it may be that Pagodaporella was 
like Dasycladus but with fewer, thicker branches, and that a thickened fleshy stem- 
cell wall bulged outwardly rather than inwardly between branches and was then 
calcified more heavily than in Dasycladus. (Fig. 4). If this were so the Pagoda- 
porella skeleton would represent the calcification between swelling primaries, but 
separated from the level of their points of insertion by the thickness of the externally 
intermittently swollen stem-cell wall. In this way the present internal cavity of the 
fossil would be a record of the maximum diameters of the stem-cell, and the thin 
points of insertion of the primaries would have been some little distance inside the 
cavity. 

Pagodaporella is therefore tentatively referred to the Dasycladeae : we know that 
branched choristospore laterals, seen in living genera of the tribe, had already 
evolved by the Palaeocene from the evidence of heavily calcified genera, e.g. Cymo- 
polia. This structure may well have been present in Pagodaporella, even if no 
calcified evidence remains, and it may be that the genus is ancestral to the living 
Dasycladus : reduction of calcification and increase in number of branches seems a 
likely evolutionary trend. 

Genus PALAEODASYCLADUS Pia 1927 
{PALAEOCLADUS Pia 1920 non Ettingshausen 1885) 

Diagnosis. Elongate near-cylindrical club-shaped calcified dasyclad, showing 
numerous successive verticils of strongly-inclined branches : the branches show 
primaries, dividing into clusters of four to six secondaries, in turn dividing into 
clusters of four to six tertiaries. All branch-segments slightly swollen : successive 
verticils show a progressive elaboration of branch-detail. 

Palaeodasycladus mediterraneus Pia 

(PL 16) 

1920 Palaeocladus mediterraneus Pia : 118, pi. 6, figs. 1-5 ; text-fig. 22. 

1927 Palaeodasycladus mediterraneus Pia : in Hirmer's " Handbuch der Palaobotanik ", Bd.i 

79- 
i960 Palaeodasycladus mediterraneus Pia ; Elliott : 221. 

Description (from Middle East material). Near-cylindrical elongate club-shaped 
dasyclad, length 7-8 mm. or more, external diameter increasing slowly and regularly 
from 1 mm. or a little less at the base to about 2-4 mm. in the terminal expansion, 
internal diameter from about 50% of corresponding external measurement at the 
base to about 30% or less at the terminal expansion i.e. the stem-cell cavity diameter 
increases only slowly compared to the external measurement. Close-set successive 
verticils of branches, 5 or 6 per mm. of measured length in mid-thallus : each verticil 



62 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



with up to 20 branches, in which the primaries are inclined outwards and upwards at 
45-50 ° from the horizontal, and the subsequent branchlets curve outwards at a 
lessening angle. Each primary gives rise to four or more secondaries, and these in 
turn to about the same number of tertiaries ; all branches and branchlets are sharply 
constricted terminally, slightly swollen between to give a slim sausage-shaped out- 
line, and the tertiaries may themselves be constricted, without branching, before the 
final termination expansion. The branches from the lower verticils, at lesser 
diameters, are simpler in structure than the much larger terminal ones : the 
transition is gradual. 

Horizon. Lias of Southern Europe, North Africa and the Middle East. 

Material. Numerous random thin-sections from one level in the median 
dolomitic limestone of Group a (Liassic) of the Lower Musandam Limestone ; 
Wady Bih, Jebel Hagab, Peninsular Oman (Hudson & Chatton 1959). 

Remarks. Palaeodasycladus mediterraneus is a characteristic and locally- 




Fig. 5. Reconstruction (after Pia 1920) of Palaeodasycladus mediterraneus Pia. Vertical 
section on left ; decalcified appearance on right. X12 approx. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 63 

abundant microfossil in the Lias of the circum-Mediterranean area, namely Spain, 
Italy, Greece, Morocco and Algeria. Its total range appears to be from within the 
upper part of the Lower Lias, through the Middle Lias, and into the lower part of the 
Upper Lias ; there are records from top Triassic which need confirmation (Sartoni & 
Crescenti 1962). The usual associated microfossil is the foraminifer Orbitopsella 
praecursor (Giimbel) . In the Middle East P. mediterraneus is known to me only from 
Oman, where it is locally abundant in one bed of the Dolomitic Limestone of the 
Lower Musandam, associated with algal nodules, and probably of Middle Liassic age 
(see Hudson & Chatton 1959 : 78). Orbitopsella is known from S.W. Persia, but I 
have not seen Palaeodasycladus associated in this limestone, though it is likely to 
occur there. A. Gollestaneh has, however, recently discovered this dasyclad in the 
lower to middle Lias of Khaneh Kat, interior Fars province. It is interesting that in 
Oman, Orbitopsella occurred more or less throughout the Liassic rocks, whilst 
Palaeodasycladus was restricted to one bed : in southern Italy, however, the alga has 
a much greater vertical range than the foraminifer (Sartoni & Crescenti, 1962 ; de 
Castro 1962). 

P. cf. mediterraneus from the subsurface Jurassic of Haifa, Israel, is Middle 
Jurassic in age (Maync, 1966 ; Derin & Reiss 1966). 

In general, the Oman material confirms the accuracy of Pia's original reconstruc- 
tion of Palaeodasycladus (Pia 1920 : 121). Sizes reached are less than those of large 
Italian specimens, for which 12 mm. length and 2-8 mm. maximum external diameter 
are quoted (Sartoni & Crescenti i960 : 14). Although the dolomitised nature of the 
Oman specimens is not ideal for elucidation of fine detail, there appear to be several 
small differences. The ragged outline of the stem-cell cavity, clearly figured by Pia 
and ascribed by him to incomplete inner calcification on alternate verticils, was only 
seen on one incomplete example, where it may well be due to the dolomitisation of the 
stem-cell filling. The branches, although constricted as figured by Pia, appeared less 
swollen and slimmer than in his reconstruction, and although constriction of tertiaries 
without branching does occur, it was much less marked than in his figures. Finally 
Pia's reconstructed successive cross-sections [op. cit. : 121), show a reduction in the 
number of branches per verticil, from base to apex, 18 to 12, so accommodating the 
increased branch-complexity. In the Oman material this is much less obvious, if it 
occurs at all, and although counts of branching are difficult on sections of this 
crowded, highly-oblique, structure, about 20 branches have been counted at a large 
verticil. This is apparently to be correlated with the thinner branches already noted. 
It is suggested that Palaeodasycladus retains the number of branches per verticil 
during growth, or even increases them slightly like many other dasyclads, and that 
the reduction seen in Pia's admirable clear figures is a cartographic necessity rather 
than an accurate depiction. 

The Oman material is referred here to P. mediterraneus, and there is no reason to 
make it a new species or variety. It is not comparable with the distinctive P. 
mediterraneus elongatulus (Praturlon 1966). 

The modern appearance of Palaeodasycladus is striking when compared with some 
of Pia's other bizarre reconstructions from the Mesozoic. Probably the spores were 



64 CALCAREOUS ALGAE OF THE MIDDLE EAST 

borne in the swollen branches. It is easy to see how such an alga, with development 
of separate reproductive bodies, would resemble certain living genera, e.g. Dasycladus 
itself, allowing for the very different calcification. 

The Oman Palaeodasycladus-limestone is crowded with examples of the species : 
presumably they grew in dense patches or thickets like the living Dasycladus. Their 
ecology is further discussed below. 

Genus PERMOPERPLEXELLA gen. nov. 

Diagnosis. Thin hollow calcified elongate claviform dasyclad ; walls showing 
consecutive horizontal verticils of large cylindrical branches, rounded in cross- 
section, pores (branches) of adjacent verticils set alternately, all pores separated by 
narrow interstices ; proximal and distal terminal openings to thallus. 

Horizon. Permian of Iraq. 

Type Species. Permoplexella attenuata sp. nov. 

Permoperplexella attenuata sp. nov. 

(PI. 17, figs. 1-5) 

Description. Hollow elongate calcified club-shaped thallus, length about 2-5 
mm., external diameter increasing gradually from 0-5 mm. near the base and 
swelling to 0-9 mm. or more sub-terminally, internal diameters 45-46% external, 
ends rounded, terminal apertures of about 0-156 mm. and 0-312 mm. diameter 
respectively. About 22 consecutive verticils each of about 20 branches, branches in 
successive verticils arranged alternately. The branches in vertical section are seen 
to communicate with the internal cavity by a narrow pore, and expand at once to a 
rounded rectangular section, occasionally seen as flask-shaped in the terminal 
expansion of the thallus. In cross-section they are rounded-polygonal, about o-i 
mm. diameter, and separated by calcareous interstices of 0-020 mm. or less. Traces 
of a narrow longitudinal calcified structure within the central cavity. 

Horizon. Permian of Iraqi Kurdistan. 

Holotype. The specimen figured in PI. 17 fig. 4, from the Permian Zinnar 
Formation ; Ora, Mosul Liwa, Iraq. V. 52085. 

Paratypes. The specimens figured in pi. 13 figs. 1-3, 5 ; same locality and 
horizon. V. 52084, 52085. 

Other Material. Random sections in the same samples. 

Remarks. The little dasyclad described above, although distinctive enough in 
the Iraqi Permian flora studied, shows a combination of characters which are not 
themselves intrinsically distinctive. The pores (side-branches of the verticils) are 
simple and do not consistently show any of the shapes characteristic of the different 
genera of the diploporeae — Diplopora, Gyroporella, Physoporella, etc. Although the 
thallus is that of the conventional single dasyclad, the terminal apertures suggest 
that it may possibly be a unit of a serial plant ; for whilst it is true that in some of 
the more elaborate dasyclads of later geological periods the distal aperture is occupied 



CALCAREOUS ALGAE OF THE MIDDLE EAST 65 

by a tuft of narrow sterile branches, we do not know whether these simple-branched 
late Palaeozoic dasyclads were similar in this respect. The fossil is presumably not 
to be regarded as a new small species of Eogoniolina Endo, which has no distal 
aperture ; its branches are not those of Gyroporella, and it is smaller and with 
different shaped thallus than the somewhat doubtful Pseudogyroporella (Endo 1959). 
Although segments of Mizzia spp. auct. vary considerably, the fossil under discussion 
is outside the known range of segment-shape for this genus. It is moreover rare 
amongst an abundance of Mizzia, and the calcareous traces in the stem-cell cavity, 
never seen in any of very many Mima-segments examined, suggest a different 
internal organisation. It seems best to admit that its exact place amongst the 
dasyclads is at present obscure, and to describe it as a new genus, tentatively 
referable to the tribe Diploporeae. 



Genus PIANELLA Radoicic 1962 

Diagnosis. Calcified cylindrical dasyclad tube showing successive verticils of 
horizontally directed branches, alternating in position from one whorl to the next : 
branches simple, unbranched, widening evenly outwards from a narrow insertion at 
the stem-cell cavity to the anterior : i.e. differing only from Macroporella in the 
regular verticillate, instead of irregular, insertion of the branches at the stem-cell. 



Pianella gigantea (Carozzi) Radoicic 

1955a Macroporella gigantea Carozzi : 43, pi. 6, fig. 4 ; text-fig. 7. 

i960 Macroporella gigantea Carozzi ; Elliott: 221. 

1962 Pianella gigantea (Carozzi) Radoicic ; Radoicic : 202. 

Description (based on Carozzi). Calcified cylindrical dasyclad tube of 1-2-1-75 
mm. external diameter, internal diameter 66-70% of corresponding external diameter; 
successive verticils of horizontally directed branches, 30-40 per verticil, widening 
from 0-03 mm. diameter internally to 0-09-0-20 mm. externally to give a regular 
external pattern of polygonal pores. 

Horizon. Upper Jurassic of Europe (Switzerland) and Arabia (Oman, Hadhra- 
maut). 

Material. Upper Jurassic of Jebel Kaur, Oman ; also in derived Upper 
Jurassic in the Upper Cretaceous Hawasina-complex at Jebel Buwaida, Ibri, Oman. 
Fragmentary remains in Upper Jurassic of the Jebel Laut area, Wahidi State, 
Hadhramaut, and see also Hadhramaut record of Beydoun (i960 : 140). 

Remarks. Carozzi described his species from the Sequanian-Portlandian of the 
Swiss Upper Jurassic. Associated fossils and stratigraphy suggest the upper part of 
the Upper Jurassic for the Middle East occurrences also. The species is apparently 
uncommon there and remains are fragmentary or poorly preserved. Praturlon 
(1966) relegates this species as a synonym of P. pygmaea (large individuals). 



66 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Pianella pygmaea (Gumbel) Radoicic 
(PI. 17, figs. 6-8) 

1891 Gyroporella pygmaea Gumbel : 306, text-figs. 6, 7. 

1924 Macroporella pygmaea Gumbel spec. ; Pia : 84, pi. 1, figs. 4-7. 

1955a Macroporella pygmaea Gumbel ; Carozzi : 40, pi. 6, fig. 3 ; text-figs. 5, 6. 

i960 Macroporella pygmaea (Gumbel) ; Elliott : 222. 

1962 Pianella pygmaea (Giimb.) Rad. ; R. RadoiciC : 202. 

Description. Calcified cylindrical dasyclad tube, external diameter 0-33-078 
mm., internal diameter 0-10-0-34 mm. (d/D 27-43%, usually about 30%), showing 
consecutive horizontal verticils of branches, about 18-20 verticils per mm. of length, 
each verticil of 15-20 branches. The branches are straight, unbranched, near- 
circular in cross-section, and widen radially with straight sides to the exterior, from a 
very narrow insertion on the stem-cell cavity to the exterior where they have a 
diameter of about 0-052 mm., sometimes with a terminal widening to give a diameter 
of 0-090 mm. 

Horizon. Upper Jurassic to bottom Cretaceous (Sequanian-Valanginian) of 
Central and Southern Europe (Switzerland, Italy, Southern Germany), Middle East 
and Borneo. 

Material. In the Middle East, from the Garagu Formation (Valanginian), sub- 
surface at Awasil no. 5 well and Mileh Tharther no. 1 well, both Dulaim Liwa, Iraq. 
Also from the Upper Jurassic of the Jebel Laut area, Wahidi State, Hadhramaut, 
and see Hadhramaut record of Beydoun (i960 : 140). 

Remarks. P. pygmaea from the Middle East is closely comparable in dimensions 
and structure with the European material described by Pia and by Carozzi (ref. 
Carozzi 1955a). The external diameter of the pores is usually less (0-05 mm. com- 
pared with 0-09 mm.), though not invariably so. Of comparable species, P. grudii 
Radoicic, from the Kimmeridgian of Jugoslavia, is a smaller species with proportion- 
ally wider stem-cell ; P. tosaensis Yabe & Toyama, from the Upper Jurassic of Japan, 
shows about 30 branches per verticil, and these are polygonal in cross-section, with 
expanded outer terminations. 

Genus PSEUDOEPIMASTOPORA Endo 1961 

Diagnosis (after Endo). Thallus short-elliptical, somewhat undulating, almost 
circular in cross-section ; branches widening within the wall-thickness to spherical 
cavities (believed sporangial) and narrowing again, set at right angles and slightly 
ascending to the vertical axis, and may be arranged as definite verticils. 

Pseudoepimastopora was instituted by Endo (1961) to include those species of the 
older genus Epimastopora s.l. in which the pores seen penetrating the walls swell from 
a narrow entry to a more or less globular cavity within the wall-thickness and con- 
strict again : these swellings were considered sporangial in origin. This left 
Epimastopora s.str. for species in which the pores traverse most of the wall thickness 
with little change in pore-diameter. Buri (1965) does not regard this division as 
significant, or of generic value. I agree that it may not be evidence of evolutionary 



CALCAREOUS ALGAE OF THE MIDDLE EAST 67 

divergence, but it forms a useful character at present in classifying these normally 
fragmentary and rather unsatisfactory dasyclads. Both these genera are normally 
represented almost entirely by wall-fragments : straight, curved or sinuous in 
section, and they are considered to be the broken remains of the very fragile thin 
hood-like outer calcification-zone of dasyclads whose stem-cell and branch-systems 
are necessarily unknown. A comparison has been made with the Carboniferous 
Koninckopora as restored by Wood (1943), who regarded them as very closely 
related. However the outer polygonal mesh of Koninckopora is very different in 
appearance to the pored walls of Epimastopora and Pseudoepimastopora, even if all 
three are representatives of a morphologically similarly-situated outer calcification- 
zone. 

The fragmentary remains of the latter two genera have led to a proliferation of 
species based on wall- and pore-measurements (see summary in Johnson 1963). 
The calcified structures themselves have usually been reconstructed as originally 
globular or tubular. Endo (1961) cited P. pertusus as type-species, and referred his 
earlier E. japonica also to the genus. Subsequently H. Fliigel (1963) has trans- 
ferred both E. likana Kochansky & Herak and E. iwaizakiensis Endo (Permian of 
Jugoslavia and Japan respectively), to Pseudoepimastopora, figuring both from the 
Middle East. P. iwaizakiensis, from the Taurus (Southern Turkey) Permian of 
which the Iraqi Kurdistan Permian is a continuation, is shown intact in presumably 
near-longitudinal section as a very thin-walled elongate-oval. (H. Fliigel 1963). 

Remains of Pseudoepimastopora, usually fragmentary, abound in the Zinnar 
Formation, the lower portion of the Chia Zairi or Iraqi Permian System. For- 
tunately one or two whole specimens have been seen, so permitting description of a 
distinctive new species. 

Pseudoepimastopora ampullacea sp. nov. 
(PI. 18, figs. 1, 2, 5-7) 

Description. Pseudeopimastopora of " waxing-and-waning " morphology, cir- 
cular in cross-section, length about 4-0 mm., diameters (three successive maxima) 
1-56, 1-43, 0-91 mm. : thin-walled, wall-thickness 0-078-0-104 mm., pores commenc- 
ing on the inside as narrow canals, and swelling within the wall-thickness to near- 
spherical cavities of 0-052-0-065 mm. diameter, with outer opening of varying size, 
commonly about half maximum diameter ; interpore spaces (solid wall) very 
narrow so that there are about 16 pores per 1 mm. of wall-length, outer apertures of 
pores believed to be close-set in alternating levels. 

Horizon. Permian of northern Iraq. 

Holotype. The specimen figured in PI. 18, fig. 1 from the Permian Zinnar 
Formation, Ora, Mosul Liwa, Iraq. V. 52089. 

Paratypes. The specimens figured in PI. 18, figs. 2, 7, Zinnar Formation, Ora 
and Harur, Mosul Liwa, Iraq. V. 52090, 52094. 

Other Material. Numerous random thin-sections : many specimens frag- 
mentary. Same formation and area. 



68 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Remarks. This species occurs in profusion in some samples as debris ; short 
curved pieces of wall showing the pore-structure. These random cuts are commonly 
at right angles to the wall and show the near-spherical cavities well ; other, tangen- 
tial, cuts may show the inner narrow initial canals, or the arrangement of larger 
external pore-openings. Larger pieces of wall showing much curvature are relatively 
uncommon, and near-complete specimens are very rare. The holotype is a longi- 
tudinal section showing two complete diameter-maxima and a third slightly crushed: 
detail not seen on this specimen is well-displayed by debris in the same thin-section. 

P. ampidlacea differs in its distinctively lesser wall-thickness and rather smaller 
pore-diameter from P. pertunda Endo (type), P. japonica Endo and P. iwaizakiensis 
Endo. Also from the coarser P. likana Kochansky & Herak, known from elsewhere 
in the Middle East (see below). In outline P. ampullacea is distinctive, though 
Endo's description of the thallus of his fragmentary P. pertunda and japonica as 
" somewhat undulating " may indicate a similar growth-form. 

Pseudoepimastopora cf. likana Kochansky & Herak 

(PI. 18, figs. 3) 4) 

i960 Epimastopora likana Kochansky and Herak : 78, pi. 4, figs. 5-10. 
i960 Epimastopora sp. Elliott : 219. 

Fragments of Pseudoepimastopora occurring in the Permian of Jebel Qamar, 
Oman, show a wall-section of 0-325 mm. thickness, with well defined ovoid pores of 
0-130 mm. median diameter in vertical section. In this section the pores appear 
oval with pointed ends, communicating with the interior by a short very narrow 
canal, and with the exterior by an even shorter one. They are close-set, though this 
feature varies in the limited material available. 

This species corresponds most closely to Ps. likana but the dimensions seem 
larger. In the type-material of the Yugoslav species the wall diameter is given as 
0-20-30 mm. (most frequently 0-25 and the pore-diameter maximum 0-07-0-10 mm. 
(misprinted as 0-7-0-10 mm.). The Oman material is insufficient to be described 
as new. 

The specimens occurred in thin-sections of limestone boulders yielding Anthro- 
coporella mercurii sp. nov. Pseudoepimastopora fragments have also been seen in 
derived Permian material in the Lower Cretaceous Upper Musandam formation of 
Jebel Hagab in the same areas. 

Pseudoepimastopora iwaizakiensis Endo 

1953a Epimastopora iwaizakiensis Endo : 120, pi. 11, figs. 7-9. 

1963 Pseudoepimastopora iwaizakiensis (Endo) ; Fliigel : 88, pi. 1, fig. 6. 

Figured by Flugel (1963) from the Permian of the Taurus, Turkey. 

Genus PSEUDOVERMIPORELLA Elliott 1958 

Diagnosis (after Elliott). " Small gregarious meandriform calcareous tubes, 
showing a free inner compact-walled tube and an outer tubular layer that is pierced 
by numerous closely set radial pores arranged to form a regular mesh ". 



CALCAREOUS ALGAE OF THE MIDDLE EAST 69 

Pseudovermiporella was described by me in some detail (Elliott 1958b) as a Permian 
problematicum, and an algal interpretation given of its structure. Kochansky & 
Herak (i960), in discussing Permian Vermiporella spp., agree as to the algal nature of 
Pseudovermiporella, but consider that it is not worthy of generic distinction from 
Vermiporella, and that the details described should be considered a " contribution 
to the knowledge of the genus Vermiporella ". Henbest (1963) regards Pseudo- 
vermiporella as a foraminifer : "A specialized, sessile form of Permian Cornu- 
spirinae " whose originally aragonitic test has undergone a distinctive diagenetic 
change. 

These three views depend on the interpretations made of the structure and 
preservation of a very distinctive microfossil. 

My account (Elliott 1958b : 420) briefly discussed and discounted the possible 
interpretations of Pseudovermiporella as a foraminifer, bryozoan, serpulid, dasyclad 
alga of conventional structure, or hemichordate. My suggested interpretation of 
the problematic fossil regards the outer mesh as the main calcified layer of a dasyclad 
of creeping or prostrate stem-cell, perforated around lateral branches, as in Vermi- 
porella. The variable inner layer or layers of grey calcite lining this in the type- 
material are regarded as a secondary deposit, not part of the organism, formed after 
death and before burial. The very distinctive thin imperforate tube found in some 
but not all specimens, within the main cavity of the outer mesh-tube, is considered 
the calcified outer surface of the early stem-cell, after the side-branches dropped off, 
behind the actively growing anterior branched portion. 

Kochansky & Herak (i960) described Jugoslav Permian species of Vermiporella, 
including V. nipponica Endo, a Japanese species to which Pseudovermiporella was 
compared by me. Vermiporella itself has a Silurian type-species, V. fragilis Stolley, 
whose dasycladacean nature has not been disputed. There has been, however, 
considerable confusion over poorly-described Permian species referred to the genus, 
and Kochansky & Herak dealt with this. They did not record Pseudovermiporella 
(or Vermiporella) sodalica in their material, but concluded (op. cit. : 72-73) that the 
main difference between four recognized species of Vermiporella (including the type) 
and Pseudovermiporella is the presence of the " free inner compact-walled tube " in 
the latter. They quoted me correctly as not having seen this structure in all 
examples, and regarded this as growth-stage detail in a very full description of a 
species of Vermiporella not worthy of generic distinction. 

Henbest (1963 : 33) interprets Pseudovermiporella as a " specialized, sessile genus 
of Permian Cornuspirinae " continuing a series formed by the earlier genera Apter- 
rinella and Hedraites, with which he compares it closely. All three are interpreted 
as originally aragonitic foraminifera which have undergone conspicuous changes 
during diagenesis : it is important that in this interpretation the inner layers of grey 
calcite lining the outer mesh are regarded as an integral part of the test itself. In 
correspondence, after examining topotype material sent by me (letter of August 17, 
1964) Henbest regards the free inner thin- walled tube as that of " a later individual 
or organism ". 

The three accounts quoted should be read for a full appreciation of the differing 



7 o CALCAREOUS ALGAE OF THE MIDDLE EAST 

interpretations of various minor points and comparisons : it is, however, believed 
that the summary above includes the essential differences. 

I described Pseudovermiporella as a problematicum, probably algal, and believe 
that the presence of the inner thin-walled tube is important. It is not recorded in 
Permian Vermiporella spp. elsewhere, and although it is not seen in all specimens, its 
occasional presence unbroken and set in clear calcite free of the outer structures 
suggests that it was part of the organism and not a later inhabitant of the abandoned 
tube. It is, however, readily admitted that the exact nature of Pseudovermiporella 
remains unknown : its description is included here as a doubtful dasyclad of the 
Middle East. Giivenc (1965), who figures un-named species or forms from the 
Taurus, leaves it as a problematicum. The microproblematicum Papillomembrana 
from the Norwegian Precambrian (Spjeldnaes 1963) bears certain resemblances, from 
the type-description. 

Note. The interesting study by K. B. Korde (Pal. Zhurn., 1966 no. 4) was seen 
too late for proper discussion here, but briefly this authoress agrees with the probable 
algal nature of Pseudovermiporella, whilst unable to place it taxonomically within 
the algae. 

Pseudovermiporella sodalica Elliott 
(PL 19) 

1958b Pseudovermiporella sodalica Elliott : 419, pis. i, 2, 3. 

i960 Pseudovermiporella sodalica Elliott ; Elliott : 219. 

1961 Pseudovermiporella sodalica Elliott ; Erk & Bilgutay ; 108, pi. 1. 

Description. Tubes of finely crystalline calcite, appearing white by reflected 
light and dark in thin section, occurring commonly with various diameters up to 
i-o mm. and sometimes attaining a diameter of 1-4 mm. The tubes are meandriform 
and form tangled growths several millimeters across, in which apparently more than 
one individual may occur. When a tube is free the cross section is circular, and 
remains approximately so in many coils or loops, which touch in a growth or tangle. 
However, when attached to others or to shell fragments, individuals occur which 
show in thin section as arcs applied closely to the object encrusted, whose outer 
surface completes the tube. 

The tubes are pierced by numerous closely set radial pores, approximately at right 
angles to the axis of the tube, separated by interpore wall material which widens 
slightly outward, or terminally, as seen in transverse and vertical sections. In adult 
individuals the pores are about 0-030-0-040 mm. in diameter, circular in cross section, 
about fifty to a transverse section of the tube, and the interpores of wall material 
sometimes show a paired appearance in both transverse and vertical section. In 
tangential sections the coarsely-pored wall shows as a regular and distinctive round- 
pored mesh, with pores wider than interpores ; a count along a 1 mm. length of such 
a section gave twenty-one regularly spaced pores. Such measurements are approxi- 
mate only, due to the coiled tubes, which are at best only sinuous and never straight. 
Smaller tubes show smaller pores. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 71 

Within the outer pored tube described above there occurs in a majority of speci- 
mens a continuous solid dark calcareous layer, attached to the inner surface of the 
outer mesh. In many specimens this layer is indistinguishable in colour and texture 
from the dark outer calcite mesh, and has the appearance of being part of the tube ; 
in some it shows as a lighter, obscurely banded layer of variable thickness, eccen- 
trically placed with regard to the outer tube, i.e. much thicker on one side than on the 
other in transverse section ; and sometimes it is absent. This layer is interpreted as 
a secondary deposit formed subsequent to the death of the tube-building organism, 
though not after burial, for occasional specimens show other organisms attached to 
its inner surface. The reason for its occurrence is discussed above. Consideration 
of the algal dust infillings described in Koninckopora by Wood (1943) did not permit 
close comparison, but the observations of Johnson (1957 : 181) are of interest. The 
lining layers in Pseudovermiporella may be of similar origin to the granular crystalline 
calcite described by Johnson, and considered by him to have been formed probably 
almost contemporaneously with deposition, whilst objects were movable on the 
sea-floor. 

Within some but not all specimens there occurs an innermost tube of thin dark 
imperforate calcite, roughly circular in cross section, and of considerably lesser 
diameter than the inner diameter of the outer tube from mesh to mesh. Sometimes 
this thin layer forms the inner boundary of the secondary layer mentioned above ; 
sometimes it is seen " free " within the central cavity, filled with transparent calcite 
and separated by the same mineral from the outer pored tube or from the dark 
secondary lining calcite if present. When intact, it is not invariably central in 
position ; not infrequently it is broken, and sometimes small organisms are seen 
attached to it. It is considered to be of organic origin, and its relation to the outer 
pored tube is discussed above. 

The smallest tubes show in section as bubble-like clusters, rather like the nucleo- 
conchs of certain foraminifera. Although some of the sections in such a cluster are 
a result of the plane of section cutting a meandriform tube more than once, it seems 
likely that more than one individual, budding from a centre, may sometimes be 
present. The walls of these tiny immature tubes are composed of the innermost thin 
dark organic calcite just described ; only when they are larger does a pored outer 
tube, with proportionally small pores, appear. There is considerable variation 
between individuals in the diameter-size at which this occurs. 

In sections of the mesh of adult individuals, small bubble-like sections of the inner 
layer of small, usually single individuals sometimes occur, suggesting attachment or 
budding. Small pored tubes occur within the tubular cavities of larger individuals, 
attached either to the inside of the main outer mesh (rarely to the secondary calcite 
lining this, if present) ; or to the outside of the inner, thin-walled tube. They are 
never found within the latter when it is unbroken. 

Horizon. Upper Permian of the Middle East. 

Material. Very numerous thin-sections from Permian limestone at Jebel Qamar, 
Peninsular Oman, Arabia (foraminiferally dated as probably Upper Permian by 
Dr. M. C. Chatton). Seen also in derived Permian material in Upper Cretaceous, 



72 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Tawi Silaim, Oman. In Iraq this species (or a comparable species of Vermiporella) 
occurs rarely in the Upper Permian Darari Formation of Harur, and in the subsurface 
Upper Permian of Atshan no. i well, both in Mosul Liwa. Recorded by Erk & 
Bilgutay (1961) from the Permian of Sarikaya, Diskaya Mountains, near Bursa, and 
from the Adana Basin, Turkey. 

Remarks. See discussion under " Genus Pseudovermiporella " above. 

Pseudovermiporella elliotti Erk & Bilgutay 

1961 Pseudovermiporella elliotti Erk and Bilgutay : no, pi. 2. 

Remarks. This species appears similar in many characteristics and in mode of 
growth to the type-species. It differs, however, in the following points, summarized 
from the authors' description and comparisons. It is a smaller species (external 
diameter up to 0-539 mm -)> the pores are hexagonal, not rounded in cross-section and 
both smaller in diameter (0-025-0-030 mm.) and more closely set (interpores of o-oio- 
0-013 mm. thickness). The individuals are said to occur singly, and not tangled or 
closely associated as in P. sodalica. It is not clearly stated whether an inner thin- 
walled tube occurs, though small individuals occur within larger ones, as in the larger 
species. It is recorded from the Turkish Permian at Kozan, Adana Basin and from 
various localities near Ankara. In the Adana area the two species occur commonly 
in rocks of Middle Permian age. 

Genus SALPINGOPORELLA Pia 1918 

Diagnosis. Small, rod-like, thick-walled, calcified, tubular dasyclad, with regular 
successive verticils of relatively few simple single branches which widen to the 
exterior and open as simple pores : thallus not segmented, but interverticil portions 
sometimes outwardly slightly convex and delimited by grooves. 

Salpingoporella annulata Carozzi 
(PI. 20, figs. 3, 4, 6, 7) 

1953 Salpingoporella annulata Carozzi ; 384, figs. 1-55. 

1955b Salpingoporella annulata Carozzi ; Elliott : 125, 126. 

1955a Salpingoporella annulata Carozzi ; Carozzi : 55, pi. 6, figs. 5-7, text-fig. 15. 

i960 Salpingoporella annulata Carozzi ; Elliott : 221. 

Description (based on Carozzi). Small, tubular, calcified dasyclad, straight or 
slightly curved and usually occurring in fragments of up to 1 mm. or more in length, 
external diameter 0-30-0-64 mm., internal diameter 0-10-0-25 mm. The thick walls 
perforated by horizontal verticils of branches at about 0-15-0-20 mm. apart, each 
verticil consisting of 8-12 simple straight radial branches which widen terminally 
and open in a shallow external horizontal annular groove. Pores alternate in 
position from one verticil to the next, and between them the external interverticil 
walls are gently convex. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 73 

Horizon. Upper Jurassic-bottom Cretaceous (Kimmeridgian, Portlandian- 
Valanginian) of Switzerland and Southern France, Italy, Jugoslavia : and of Middle 
East (Arabia) ; Qatar, Trucial Oman and Hadhramaut. 

Material. Solid and thin-section material from the subsurface Upper Jurassic 
(upper part) of the Dukhan wells, Qatar Peninsula, Arabia, where it is common ; 
also at the same level in Gezira no. i well, Murban, Abu Dhabi, Trucial Oman. Also 
from the Upper Jurassic of Al Hamiah, Coastal Wahidi, Hadhramaut ; and from 
the subsurface Lower Thamama formation (bottom Cretaceous) of Murban no. 2 
well, Abu Dhabi, Trucial Oman. 

Remarks. The Qatar material corresponds with Carozzi's type material in 
detailed morphology, number of branches per verticil, etc. : the maximum size seen 
(external diameter o-6o) is a little less than Carozzi records, and the minimum 
measurement encountered for this dimension (0-26 mm.) is also less than that given 
for the type-material. Since the closely similar 5. apenninica Sartoni and Crescenti 
(see below) differs mostly in its smaller size, a series of Qatar specimens were carefully 
measured for outer and inner diameter and spacing between verticils. Of thirteen 
such examples, only one fell completely within the limits given for the smaller species, 
and it is considered that this is best regarded as a small example of S. annulata. At 
Qatar the material consists of short lengths only of tube, occurring amongst ooliths 
and rounded fragments and often rolled, and it may be that sorting has occurred 
before burial. 

Salpingoporella apenninica Sartoni & Crescenti 
(PI. 20, figs. 1, 2, 5) 

1962 Salpingoporella apenninica Sartoni and Crescenti : 266, pi. 44, figs. 1, 2, 4, 5, 6, 8. 

Description (based on Sartoni & Crescenti). Small tubular calcified dasyclad, 
straight or slightly curved and usually occurring in fragments of up to 1 mm. or more 
in length, external diameter 0-19-0-32 mm., internal diameter 0-097-0-22 mm., the 
walls perforated by horizontal verticils of branches at about 0-08-0-16 mm. apart, 
each verticil consisting of 8-14 simple radial branches widening terminally and 
opening in a shallow horizontal annular groove. Pores alternate in position from 
one verticil to the next, and between them the external interverticil walls are gently 
convex. 

Horizon. Upper Jurassic-bottom Cretaceous (Kimmeridgian, Portlandian- 
Valanginian) of Italy : Upper Jurassic of Iraq. 

Material. Abundant thin-sections from the subsurface Najmah Formation 
(Upper Jurassic) of Kirkuk no. 117 well ; also rarely in the subsurface Jurassic of 
Mileh Tharthar no. 1 well, Dulaim Liwa, believed to be a caving from the Makhul 
Formation (Tithonian) in this well. Both localities are in northern Iraq. 

Remarks. The Iraqi material corresponds well in morphology and dimensions 
with the Italian type-material (external diameters of 0-208-0-286 mm., internal 
diameters of 0-104-0-130 mm.). This species is very similar to 5. annulata : the 



74 CALCAREOUS ALGAE OF THE MIDDLE EAST 

principal difference in thin-section is that whilst the stem-cell diameters are slightly 
less in 5. apenninica, the external diameters are much less, so that the percentage 
relation of internal to external is greater (50-60% against 33-40%). In 5. annulata 
the distance between the external pores of the same verticil is said to be about equal 
to the distance between two successive verticils (Carozzi 1955a) ; in S. apenninica the 
former is less than the latter. The two species are very similar and obviously 
closely related : in examining a series of either one finds atypical specimens showing 
measurements more usual in the other species. In Italy they occur together over 
the same range : in the Middle East they are apparently separate, S. annulata in the 
south at Qatar and elsewhere, and 5. apenninica in the north in Iraq. Both these 
occurrences are often in a similar oolitic facies, with associated fossils in common 
(Clypeina jurassica, Favreina salevensis, Cladocoropsis, etc.). 

Salpingoporella arabica sp. nov. 

(PI. 21, figS. I-3) 

1955b Salpingoporella cf. miihlbergii (Lorenz) ; Elliott : 126. 

i960 Salpingoporella muhlbergi (Lorenz) , and 5 . muhlbergi var ; Elliott: 222-224. 

Description. Thin-walled tubular calcified dasyclad, straight-sided with very 
gentle increase in diameter ; observed lengths (incomplete) up to 273 mm., external 
diameter 0-31-073 mm., internal diameter 0-21-0-47 mm. ; ratio of internal to 
external diameters 55-66% ; horizontal verticils set regularly 0-104 mm - apart, each 
verticil with 8-10 branches which open rapidly and widely to external pore- 
depressions of 0-065-0-078 mm. or more diameter. The wall calcification is thin and 
rather ragged : the pores have a somewhat irregular appearance, partly due to the 
wall-structure and partly due to slight irregular deviations from the horizontal in 
their orientation. 

Horizon. Lower Cretaceous of the Middle East. 

Holotype. The specimen figured in PI. 21, fig. 3, from the Qamchuqa Formation 
(Aptian-Albian level) of Surdash, Sulemania Liwa, Iraq. V. 52102. 

Paratypes. The specimens figured in PL 21, figs. 1, 2, from the top Qamchuqa 
Formation (Albian level) of Sarmord, Sulemania Liwa, Iraq, and from the Upper 
Musandam Formation (Lower Cretaceous) of Jebel Hagab, Peninsular Oman, 
Arabia. V. 52100, 52101. 

Other Material. In Iraq, Qamchuqa Formation of Zibar-Isumeran, Mosul 
Liwa (Barremian-Aptian level) ; Sarmord Formation of Jebel Gara, Mosul Liwa 
(Valanginian-Hauterivian) and of Sarmord, Sulemania Liwa (Barremian). In 
Arabia, from Haushi, South Oman, Lower Cretaceous probably Valanginian-Hauteri- 
vian ; also from subsurface Upper Thamama Formation, ? Barremian-Aptian level, 
of Murban no. 2 well, Abu Dhabi, Trucial Oman. 

Remarks. S. arabica is the Middle East form of the European S. miihlbergii 
(Lorenz) Pia, with which I earlier tentatively identified it. The European species 
from the Barremian-Aptian of France and Switzerland and the Lower Cretaceous of 



CALCAREOUS ALGAE OF THE MIDDLE EAST 75 

Italy (Lorenz 1902 ; Pia 1918, 1920 ; Thieuloy 1959 ; Sartoni & Crescenti 1962), is a 
slightly smaller species normally (external diameter 0-3-0-5 mm.), though Thieuloy 's 
figures appear to indicate up to 1-5 mm. for this dimension. It is however much 
thicker-walled, the relation of internal to external diameters being about 40% (38- 
45%) as against 60% (55-66%) in S. arabica. Because of this, the branches in the 
latter rarely show much of the inner narrower portion seen in the European form, if 
indeed this was ever present. S. texana from the Albian of U.S.A. (Johnson 1965), 
compared by its author with S. miihlbergii, may similarly be distinguished from 
S. arabica by dimensions and proportions. 

S. arabica ranges from bottom Cretaceous as high as Albian ; it is wide-spread, 
but rarely abundant. 

Salpingoporella dinarica Radoicic 
(PI. 21, fig. 4 ; PI. 22) 

1959 Salpingoporella dinarica Radoicid : 33, pis. 3-5. 
i960 Hensonella cylindrica Elliott : 229, pi. 8, fig. 1. 

The descriptions of Radoicic (1959) and myself (Elliott i960) refer to the same 
organism. Radoicic interprets this as an alga, and described it as a species of 
Salpingoporella, comparing it carefully with S. miihlbergii of the same age. I 
described it as a problematicum, since my interpretation of the wall-structure 
indicated that it differed very considerably from other dasyclads. 

This organism is Tethyan Lower Cretaceous in age, and is especially characteristic 
of the Barremian-Aptian level. The type-description of S. dinarica lists it from 
numerous localities in Jugoslavia at this horizon, and Sartoni & Crescenti (1962) and 
de Castro (1963) figure and record it under the algal name, with Hensonella in 
synonymy, from the Aptian of Italy. Elliott (i960 ; 1962a) recorded Hensonella 
from Iraq and Oman (a full list of Middle Eastern localities is given below), Persia, 
Algeria and Borneo : Lower Cretaceous, various levels. It has also been seen in 
material from the Upper Aptian, Mededine area, S. Tunisia. Reiss (1961) recorded 
it from the Aptian of Galilee, Israel, and regarded it as a dasycladacean alga. Dr. 
M. S. Edgell {in litt., May i960) also stressed the dasycladacean nature of Iranian 
material. 

Most of these records clearly refer to the same organism. Comparison of 
Radoicic's and Elliott's descriptions show that the same features are common to 
both, though the type-figures selected emphasize slightly different characteristics. 
The organism occurs as hollow cylindrical or near-cylindrical tubes, circular in cross- 
section, and of varying external diameters up to 0-57 mm. The internal diameter 
varies from 54-70% of the external : lower values up to 60% or a little more are 
more common. The walls show a thin inner dark amorphous layer, finely micro- 
crystalline under a high power, and a thick outer layer (0-013 mm - an d 0-104 mm - 
respectively in one typical example). This latter, which occupies most of the wall- 
thickness, is yellowish in thin-section appearance : it shows innumerable fine radial 
subparallel lines or cracks, and, at intervals, coarse canals which extend to widen at 
the outer surface to occasion shallow pores. In specimens of regular form these are 



76 CALCAREOUS ALGAE OF THE MIDDLE EAST 

arranged at regularly-spaced levels, the pores alternating in position from level to 
level, and Radoicic, who figured them as dasyclad verticils of lateral branches, 
indicated (op. cit., fig. i) that the distance between adjacent external pores of one 
verticil was twice the distance between successive verticils. In Radoicic's type- 
figures, e.g. pi. 4, fig. 1, this regularity is very clearly shown, and other writers, e.g. 
Reiss 1961 (figs. 101, 105, etc.) also show this. In the types of Hensonella (Elliott 
i960, pi. 8, fig. 1) this regularity is absent, and I drew attention to the irregularity. 
Reiss (op. cit. : 229), commenting on this, adds that the pores " occur in all suitably 
sectioned specimens ", meaning presumably sections taken at pore-level, and such 
specimens have been seen not uncommonly in slides of Middle East Hensonella. 

The thick yellowish layer was described for Hensonella (Elliott i960 p. 229) as 
aragonite. This was incorrect : it is calcite, and both Dr. A. Lees (Reading Univer- 
sity) and Mr. J. McGinty (Iraq Petroleum) consider it derived from an original 
organic calcite structure. 

Crushed examples from Algeria show the thick layer broken along radial partings, 
but in most cases still held together by the inner thin dark layer. If the crushing 
occurred during compaction, this suggests original organic nature for the thin layer, 
with some flexibility. Edgell (in lit., i960), who also supported the dasyclad nature 
of the organism, suggested that this layer may be the original algal wall, or thickened 
organic outer layer of the stem-cell, and this appears to be the view of Radoicic also 
(op. cit. : 38). That it was an original part of the organism is indicated both by its 
almost invariable presence irrespective of all but the very worst preservation, and by 
occasional specimens in which it is lined by a secondary inner layer of post-mortem 
calcite, possibly pre-burial, the actual tube-core within this being clear, transparent 
calcite deposited after burial from solution. The large canals which expend to the 
exterior are sometimes seen in random cut to reach this dark inner layer, and, 
following Reiss's reasoning on their external appearance, may similarly be supposed 
normally to do so when the sections are suitably orientated. 

Summarizing, S. dinarica Radoicic and Hensonella Elliott were described from 
examples of the same organism, and the great majority of subsequent records refer 
to this same species. Slight differences in the two author's descriptions can be 
reconciled by examination of large sets of specimens. Since the fossil agrees in size, 
shape, and morphological structure with other dasyclads, and also occurs in suitable 
facies at suitable levels for this, Radoicic described it as a dasyclad, referring it to 
Salpingoporella and comparing it carefully with S. miihlbergii of the same age. A 
similar comparison is possible with the new S. arabica. This dasyclad reference 
seems to be the majority view of other workers, as expressed in synonymy or by 
comment. 

In spite of this, there remain certain doubtful features which seem incompatible 
with a dasyclad origin. In living dasyclads, the deposition of the original aragonitic 
calcium carbonate is connected with the " assimilatory processes in the chlorophyll 
corpuscles " (Church 1895), and the calcified layers or structures built up of fine 
granules are amorphous. By contrast, the calcium carbonate of marine inverte- 
brates (molluscs, brachiopods, corals, echinoderms, etc.) is deposited out of solution 



CALCAREOUS ALGAE OF THE MIDDLE EAST 77 

by a wet membrane to give normally a lamellar structure, whatever the varied 
microstructure (fibrous, prismatic, etc.). This difference in structure makes the 
algal calcium carbonate much less resistant to diagenetic changes than that of almost 
any other fossil, with frequent disastrous results familiar to the palaeontologist. 

Ignoring near-pure limestones in which the results of calcium carbonate solution- 
replacement mechanisms are common, it is seen that in the marly facies in which 
Hensonella (or S. dinarica) abounds the undoubted dasyclads such as Actinoporella, 
Munieria and Cylindroporella and other species of Salpingoporella, show skeletal 
remains preserved as white replacement calcite, coarsely crystalline in thin-section 
under moderate magnification. This is interpreted as diagenetic replacement of 
original aragonite. Hensonella stands out conspicuously by its translucent yellow 
radially-fibrous structure. This structure represents a diagenetic alteration of 
original calcite, not originally amorphous as in some other algae, and not of aragonite. 
The radial structure is original, a point emphasized by compaction-fractured speci- 
mens, and alteration has taken place in the wall-material between these partings, and 
not to obliterate them. Only very rarely and incompletely has a later change 
affected this resistant structure, and then not to the extent seen in associated 
dasyclads. These undoubted dasyclads, sealed in the same matrix and subjected to 
the same treatment, have behaved differently. 

The thin inner dark layer is also anomalous for a dasyclad. If, as suggested by 
Edgell, it represents the thickened cell-wall of the stem-cell, then this is unusual in 
living dasyclads and not seen in fossil forms. In Hensonella it is consistently present 
under varied conditions of preservation from very different localities, which suggests 
that it originates from an original feature of the organism, even if diagenetically 
altered, and not from diagenesis itself. Moreover, although localized thickening of 
the outer stem-cell wall is known in the living Dasycladus, there is no trace of this 
preserved in the fossil Pagodaporella now considered related (see above, under 
Pagodaporella), even though the former presence of the structure is inferred. 

In conclusion, I consider that this organism is best classified as a problematicum. 
The original comparison with a scaphopod appears unlikely, but the wall-material is 
not that of known dasyclads, and certainly not that of the associated dasyclads in 
the same beds. 

Appendix. List of Middle East materials referred to Hensonella. 

In Iraq, Qamchuqa Formation (Barremian level) of Sarmord, and Sarmord 
Formation (Barremian-Aptian level) of Sekhaniyan, both Sulemania Liwa ; sub- 
surface Garagu Formation (Valanginian-Hauterivian) of Kirkuk no. 116 well 
Bottom lower Cretaceous, probably Valanginian, at Haushi, South Oman, Arabia. 
Common at Barremian-Aptian level in south-west Persia, and recorded from the 
Aptian of Galilee, Israel (Reiss 1961). 

Genus TERQUEMELLA Munier-Chalmas 1877 

1877 Terquemella Munier-Chalmas : 817. 

1920 Terquemella bellovacina Munier-Chalmas ; Costantin : 1031-32. 

1922 Terquemella Munier-Chalmas ; Morellet : 18. 



7 8 CALCAREOUS ALGAE OF THE MIDDLE EAST 

Diagnosis. Small, disc -like, lenticular or spherical calcareous bodies, with 
numerous tiny subdermal spherical sporangial cavities, the bodies themselves 
considered dissociated sporangial structures from Dactyloporeae (Dasycladaceae). 

Terquemella bellovacina Munier-Chalmas 
(PI. 23, figs. 6, 7) 

1920 Trequemella bellovacina Munier-Chalmas ; Costantin : 1031-32, figs. 13, 14. 

1922 Terquemella bellovacensis Munier-Chalmas ; Morellet : 18, pi. 1, figs. 67-76. 

1955b Acicularis sp. Elliott : 126, pi. 1, figs. 11 (right-hand fig.), 12. 

1956 Terquemella bellovacina Munier-Chalmas ; Elliott : 332. 

Description. Flattened, discoidal, solid calcareous bodies, approximately 
circular or well-rounded irregular in outline, diameter about 0-57 mm. (up to 0-65 mm. 
maximum seen), thickness 0-117 mm. (up to 0-143 mm. maximum seen). Hollow 
globular cavities of about 0-045-0-055 mm. diameter occur just within the outer edge 
of both surfaces, so that transverse (vertical) sections show two rows each of 8 
cavities, and tangential-horizontal sections show cavities scattered over the whole 
section. 

Horizon. Palaeocene of France and of Iraq ; possibly also Central America 
(Johnson & Kaska 1965). 

Material. Thin-sections from the Sinjar Formation (Palaeocene-Lower Eocene) 
of Sirwan (Sulemania Liwa), and Banik (Mosul Liwa), Iraq. 

Remarks. The Iraqi species is compatible with the details of the Morellets' 
description and figures, and the Munier-Chalmas' figures as reproduced by 
Costantin. T. lenticularis Pia, Rao & Rao (1937) from the Indian Eocene is similar 
but smaller. 

Terquemella globularis Elliott 
(PI. 23, figs. 5. 8) 

1956 Terquemella globularis Elliott : 332, pi. 2, fig. 2. 

Description. Near-spherical or flattened ovoid solid calcareous body about 
0-390 mm. in diameter, globular sporangial cavities 0-033-0-039 mm. in diameter just 
within outer edge over whole surface, so that equatorial sections show a circle of 
about eighteen of them, and tangential sections about 0-170 mm. in diameter show 
eight. 

Horizon. Palaeocene of Iraq. 

Material. Iraq : Kolosh Formation (Palaeocene and Lower Eocene) of Bekhme 
and of Rowanduz, both Erbil Liwa ; Sinjar Formation (Palaeocene-Lower Eocene) 
of Sirwan, Sulemania Liwa, and of Chalki, Mosul Liwa. 

Remarks. Not known from outside Iraqi Kurdistan, though Praturlon (1966) 
records a T. cf. globularis from the same level in Italy. T. parisiensis Munier- 
Chalmas, from the Paris Basin Middle Eocene, is of similar shape but larger (diameter 
0-5 mm.) and with fewer sporangial cavities. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 79 

"TERQUEMELLA s.l. " sp. 

Minute circular cross-sections of marginally sporangial bodies have been noted not 
uncommonly in Upper Jurassic and Lower and Upper Cretaceous rocks. These are 
presumably algal remains corresponding morphologically to Terquemella, but are 
unlikely to originate from Dactyloporeae like the Tertiary Terquemella spp. They 
show insufficient detail to be of much stratigraphic value. Similar bodies have been 
described elsewhere e.g. from the French Jurassic (Dangeard 1931). 

Genus TEUTLOPORELLA Pia 1912 

Teuthporella is mostly a Triassic genus, but Upper Jurassic species have been 
described from Switzerland (T. obsoleta Carozzi 1954) and Italy (T. socialis Praturlon 
1963b). At Jebel Buwaida, Oman, masses of derived older rocks occur in the Upper 
Cretaceous Hawasina-complex. This rubble has yielded various Upper Jurassic 
algae, including fragmentary Teutloporella sp. This derived material is probably 
from an Oman occurrence in situ of one of these species, but is insufficient for descrip- 
tion. 

Genus THAUMATOPORELLA Pia 1927 

Thaumatoporella was erected by Pia (1927) as a dasyclad genus for the Upper 
Cretaceous alga described as Gyroporella parvovesiculifera (Raineri 1922). Sartoni 
& Crescenti (1959) have shown that Thaumatoporella itself, although the name is 
valid, is not a dasyclad, and that it is the same as Polygonella (Elliott 1957) and 
Lithoporella elliotti (Emberger 1958b) . It is a single-layer lamellar or encrusting alga 
of uncertain affinities, and only occasional specimens resemble a dasyclad in section. 
Remarkable for its long range (Rhaetic to Senonian), it is common at many levels in 
the circum-Mediterranean and Middle East, but its description has no place here. 

Genus THYRSOPORELLA Giimbel 1872 

Diagnosis. Calcified tubular dasyclad showing successive verticils of radial 
branches, each branch showing several repeated divisions into smaller branches and 
branchlets, all but the last divisions swollen. 

Thyrsoporella silvestrii Pfender 
(PI. 23, figs. 1-4 ; PI. 24, fig. 5) 

1940 Thyrsoporella silvestrii Pfender : 227. 

1955b Thyrsoporella silvestrii Pfender ; Elliott : 129, pi. 1, fig. 10. 

i960 Thyrsoporella silvestrii Pfender ; Elliott : 225, 226. 

1966 Thyrsoporella silvestrii Pfender ; Massieux : 113, pi. 1, figs. 1-8. (Part 2 of this study 
(see Bibliography), in which Mile. Massieux refers T. silvestrii to Belzungia, was seen too late 
for proper discussion in this work. However, the specimens now studied from the Middle 
East show the solid walls of Belzungia, but the branch-system appears like that of Thyrso- 
porella). 

Description. Thick-walled, tubular, cylindrical calcareous dasyclad, length 



8o CALCAREOUS ALGAE OF THE MIDDLE EAST 

(observed) up to 3-5 mm., external diameter up to 078 mm., internal diameter from 
33-50%, figures in the lower half of this range being most common ; verticils of 
horizontal branches close-set, about 9 per mm. of tube-length, with six or more 
branches per verticil. Each primary branch is considerably wider than high, and in 
transverse section is markedly swollen with curved sides : a thin vertical partition 
marks the beginning of division into two secondaries, smaller but similarly swollen, 
and these in turn each divide into four little swollen tertiaries. These each divide 
into several terminal branchlets, probably four, which reach the outer surface as 
pores. On a specimen of 0754 mm. external diameter the maximum branch- 
diameters in transverse section were primary, 0-156 mm. ; secondary 0-117 mm., 
tertiary 0-039 mm -> and quaternary, about 0-015 mm. 

Horizon. Uncommon in Palaeocene-Lower Eocene of Middle East, but common 
in the Middle Eocene of the same area. Listed by Pfender (1940) from the Eocene 
of Madagascar. 

Material. In Iraq, seen from the Palaeocene-Lower Eocene Kolosh Formation 
of Sedelan, Sulemania Liwa, and from the Palaeocene of the Ghurra scarp, west- 
southwest of Wagsa, Diwaniyah Liwa. In Arabia, from the Palaeocene-Lower 
Eocene of Sahil Maleh, Batinah Coast, Oman, and from the Palaeocene of Aqabar 
Khmer, Hajer, Hadhramaut. See also Hadhramaut record of Beydoun (i960 : 
146). (The much more abundant Middle Eocene occurrences are discussed below : 
one of Pfender's records, however, is from the Palaeocene of Turkey.) 

Remarks. Thyrsoporella silvestrii Pfender was described from Egyptian Middle 
Eocene material and compared with the European Thyrsoporella cancellata Gumbel 
from the French Middle Eocene. This latter (L. & J. Morellet 1913) is a longer, 
thinner, more fragile species, with a proportionally wider stem-cell (66% of external 
diameter). Pfender recorded her species from the Middle Eocene of Egypt and 
Somalia, and also from Syria, Turkey and Madagascar. In the collections now 
studied it has been seen commonly in the Middle Eocene of north and south Iraq, and 
of Oman. 

In the Palaeocene-Lower Eocene occurrences studied for this work the species is 
rare. The records are all based on random sections, and it is possible that with a 
good series of specimens these older records might prove to be of a species or variety 
distinguishable from Pfender's species : this has not been possible so far. Pfender 
(1940) did not illustrate her paper, though this was remedied by Massieux (1966), and 
the Morellets worked on dissections of solid specimens from the French Eocene. The 
opportunity is now taken to illustrate Thyrsoporella silvestrii by figuring some good 
thin-sections of Arabian (Oman) material from the Middle Eocene. 

Genus TRINOCLADUS Raineri 1922 

Diagnosis. Calcified tubular dasyclad showing successive verticils of radial 
branches, each branch showing outwardly-widening primaries giving rise to several 
similar-shaped secondaries, and these in turn to bunches of tertiaries : branches of 
the lower verticils may not show the full detail. Branches not alternate in position 
from verticil to verticil. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 81 

Trinocladus tripolitanus Raineri 
(PI. 24, figs. 3, 4) 

1922 Trinocladus tripolitanus Raineri : 79, pi. 3, f. 15, 16. 

1936 Trinocladus tripolitanus Raineri ; Pia : 5, pi. 2, text-fig. 3. 

i960 Trinocladus tripolitanus Raineri ; Elliott : 224. 

1966 Trinocladus tripolitanus Raineri ; Massieux : 114, pi. 2, fig. 1. 

Description (based on Pia). Tubular cylindrical dasyclad, probably slightly 
club-shaped, length (observed) up to 3-36 mm., external diameters (different parts of 
thallus) from 0-47-0-68 mm., corresponding internal diameters 0-16-0-19 mm. (34- 
28%). Successive verticils, 9 or 10 per mm. of tube-length, are each of about 8 
horizontally-directed branches, which usually are not alternate in position in 
successive whorls. Each primary branch is club- or paddle-shaped in transverse 
section, widening rapidly from a narrow junction with the stem-cell and extending 
outwards through about half the wall-thickness : it then gives rise in turn to several 
smaller but similarly-shaped secondaries (perhaps five or six), and each of these in 
turn to a cluster of about six slim short tertiaries reaching the exterior as pores. 
Branches from lower verticils do not show tertiaries and may have been sterile. 

Horizon. Cenomanian or Turonian of Libya, North Africa (Raineri 1922 ; 
Pia 1936) : Turonian of France (Pfender 1940) and of Iraq and Trucial Coast, 
Arabia : Upper Cretaceous of Czechoslovakia (Andrusov 1939). 

Material. Subsurface Turonian of Ras Sadr no. 1 well, Abu Dhabi, Trucial 
Oman, Arabia, and of Musaiyib no. 1 well, Hilla Liwa, Iraq. 

Remarks. The Middle East occurrences of this species are known only by 
random thin-sections, which however correspond well in dimensions and detail to 
those of the Libyan type-material ; external diameters observed are 0-650-0-702 
mm., with corresponding internal diameters of 0-182-0-208 mm. (28-30%). More- 
over, other algae associated at the type-locality are also seen in the Middle East 
occurrences : Dissocladella undulata (Raineri) Pia at both localities and the codiacid 
Boueina pygmaea Pia as well at Ras Sadr. 

Trinocladus perplexus Elliott 
(PI. 24, figs. 1, 2, 6, 7) 

1955b Trinocladus perplexus Elliott : 128, pi. 1, figs. 16-18. 
i960 Trinocladus perplexus Elliott ; Elliott : 225. 

Description. Tubular cylindrical calcified dasyclad, probably originally slender 
club-shaped. Length (incomplete) up to 2-5 mm. seen, with external diameters 
increasing from about 0-32 to 0-44 mm., and the proportion of internal diameter to 
external constant at 53%. Fragments of smaller examples of 0-26 mm. diameter 
show an internal diameter of only 40%. The wall shows consecutive horizontal 
verticils of lateral branches : in the large example quoted the verticils are spaced at 
about 17-19 per mm. in the lower, slimmer portion of the tube, diminishing to about 
12 per mm. later. Each verticil consists of 7-10 branches : these communicate 
with the stem-cell cavity by rounded-rectangular pores. Each short thick primary 



82 CALCAREOUS ALGAE OF THE MIDDLE EAST 

divides into four secondaries : in the older, slimmer parts of the thallus this is all the 
branching seen, but in the later, wider portions each secondary divides into four 
tertiaries which reach the exterior as pores. 

Horizon. Palaeocene-Lower Eocene of Iraqi Kurdistan. 

Material. From the Kolosh Formation (Palaeocene-Lower Eocene) of Surdash, 
Sulemania Liwa ; Koi Sanjak, Erbil Liwa, and Sundur, Mosul Liwa : all in northern 
Iraq. 

Remarks. Trinocladus perplexus is the almost invariable companion of the 
codiacid Ovulites morelleti Elliott in the clastic facies or Kolosh green-rock sands of 
Kurdistan, where occurrences of the two species far outnumber occasional records of 
other algae. Trinocladus is however missing from the varied, richly algal Sinjar 
limestone and marl facies of the same age-range, where 0. morelleti is also abundant. 
This ecological distribution is considered elsewhere in this work. 

T. perplexus has not been seen outside this limited area ; its distribution is thus 
very different from that of the related Thyrsoporella silvestrii, or indeed from the 
older species Trinocladus tripolitanus. 

Trinocladus radoicicae sp. nov. 
(PI. 24, fig. 8) 

Description. Tubular cylindrical calcified dasyclad, probably originally slender 
club-shaped. Length unknown, fragments up to i-o mm. seen ; maximum observed 
diameter 075 mm. d/D ratio about 33%. Smaller transverse sections of 0-42 mm. 
and 0-34 mm. diameters show a verticil of seven branches : the primaries swell out 
markedly before dividing into thinner secondaries (probably four) and these in turn 
into several tertiaries. Specimens of smaller diameter show only primaries and 
secondaries. 

Horizon. Maestrichtian of Iraqi Kurdistan and (subsurface) Dukhan, Arabia. 

Syntypes. The specimens figured in PI. 24, fig. 8 from the Tanjero Clastic 
Formation (Maestrichtian) of Diza, Erbil Liwa, Iraq. V. 521 16. 

Other Material. Several random thin-sections from the same formation and 
horizon, Diza, Erbil Liwa, and Balambo, Sulemania Liwa, Iraq. Also similarly 
from the subsurface top Aruma of Dukhan no. 1 well, Qatar, Arabia. 

Remarks. Although the green-rock clastic facies continues in Iraqi Kurdistan 
from Tanjero Formation (Maestrichtian) to Kolosh Formation (Palaeocene), it 
contains different species of the codiacid Ovulites, 0. delicatula Elliott and 0. 
morelleti Elliott respectively. These are presumably successional in evolution. As 
already remarked, Trinocladus perplexus is the constant companion of 0. morelleti in 
the Palaeocene ; T. radoicicae is now described as the Maestrichtian associate of 0. 
delicatula. It is, however, rare and fragmentary when compared with 0. delicatula 
(itself much less common than 0. morelleti). 

T. radoicicae is similar in form, approximate size and succession of branch- 
complexity within the one thallus to T. perplexa. It differs noticeably in the form 



CALCAREOUS ALGAE OF THE MIDDLE EAST 83 

of the branches : those of T. perplexa are spindly compared to the very swollen 
primaries of T. radoicicae, where each branch takes proportionally more space and 
hence there are fewer branches per verticil. 

This species is dedicated to Mme. R. Radoicic of Belgrade, Jugoslavia, as a tribute 
to her many contributions to palaeophycology, and friendly correspondence with me. 

Genus TRIPLOPORELLA Steinmann 1880 

Diagnosis. Club-shaped calcified dasyclads with large stem-cell, close-set 
verticils of numerous branches each consisting of an elongate cylindrical primary 
containing sporangial bodies, and dividing into several thin hair-like secondaries. 

Remarks. The large and showy Triploporella spp. of the Upper Jurassic and 
Cretaceous are curiously ill-represented in the Middle East material now studied. 
No further material of Triploporella fraasi (Steinmann 1880 ; 1899) from the 
Lebanese Albian has been examined : most of this author's descriptive detail came 
from his Mexican specimens and not from the ill-preserved Lebanese fossils. Three 
other Middle East records of the genus known to the writer are all Cretaceous, all 
represented by very few random thin-sections, and none specifically determinable. 
Two, from the Lower Cretaceous of Burum, Wady Hiru Basin, Hadhramaut, and 
from the subsurface Garagu Formation (Valanginian-Hauterivian) of Makhul no. 1 
well, Mosul Liwa, Iraq, are compatible in size with such a species as T. marsicana 
Praturlon from the Italian Barremian-Aptian. The third, from the Qamchuqa 
Formation (Aptian-Albian level) of Sarmord, Sulemania Liwa, Iraq, is much smaller 
than any described species. 

IV. THE STRATIGRAPHIC SUCCESSION OF DASYCLAD ALGAE 

The stratigraphic ranges in the Middle East of most of the dasycladaceae described 
in this work are set out in Fig. 6. Before discussing these in relation to the different 
geological levels involved, the general reliability of the family for stratigraphic 
purposes must be considered. 

Dasycladaceae are sessile benthos with well-defined coastal ecologic requirements, 
the latter discussed below (p. 92). It is, therefore, rare for them to show the limited 
substage range of an ammonite species, and they are inevitably influenced by facies. 
Against this, the Tethyan coasts and shelf-seas furnished a long succession of suitable 
habitats for growth and entombment, and dasyclad euryhalinity permitted frequent 
proliferation in emergent areas when their abundance as microfossils matched that 
usual with marine foraminifera, themselves scarce or banal under these conditions. 
In the favoured area of the Middle East, therefore, (and this probably applies to 
many other areas in the Tethyan belt), I have often found it possible to date to stage- 
level by a consideration of dasyclads in association with other algae, and their 
relative abundance (cf. Elliott, i960). Supplementary confirmation from other 
fossils has been welcome, but rarely contradictory. 

A similar conclusion was independently reached by Praturlon (1966), for the Liassic 
to Palaeocene algae of the central Apennines, Italy. It is of interest to compare the 



«4 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



Anthracoporello mercurii Elliott 

Anthracoporello spectobilis Pio 

Atroctyliopsts dorariensu Elliott 

"Clypemo" sp 

Mizzio velebitana Schubert 

Permoperplexello oftenuoto EllioH 

Pseudoepimostopora ampulloceo Elliott 

Pieudovermiporella sodalica Elliott 

Paloeodosyclodus medilerroneus Pia 

Clyptma jurassica Favre 

Cylmdroporello orobico Elliott 

Pionello gigantea (Corozzi) Rodoicic 

Salpingoporello apenmnico Sartoni and Crescenti 

Griphoporello cf perforatissimo Corozzi 

Pionello pygmaea (Gumb.) Rodoicic 

Salpingoporello annulata Corozzi 

Aciculofio oniiqua Pio 

Acroporella ossurbonipoli Elliott 

Actinoporello podolico Alth 

Clypeina lucasi Emberger 

Clypemo marteli Emberger 

Clypeino parvula Corozzi 

Cylmdroporello bomesi Johnson 

Cylindroporello sugdeni Elliott 

Hemonello (Solpingoporello dinorica Rodoicic) 

Munieria baconica Deecke 

Salpingoporello orobico Elliott 

Triploporello spp. 

Clypema ipp. 

Cymopolio onadyomenea Elliott 

Cymbpol.o eochonslosponco Elliott 
Cymopolio tibetica L. Morellet 
Dissoclodella undulota (Raineri} Pio 

Dittoclodello sp. 

Neomeris cretoceo Steinmonn 

Trinoclodus radoicicoe Elliott 

Trinoclodus tripolitanus Raineri 

Aciculoria (Briardino) sp. 

8ro«ckello belgica L. & J Morellet 

Clyp*mo meriendo Elliott 

Clypeino sp. 

Cymopolio borberae Elliott 

Cymopolio kurdistanensis Elliott 

Cymopolio (Karreriaj sp. 

Dissocladello orobico Elliott 

Dissoclodella sovitnae Pio 

Forcoporello diplopora Pio 

Indopolia sofyovonti Pia 

Pogodoporello wetzeli Elliott 

Terquemella bellovacensis Mumer-Chalmos 

Terquemella globular. i Elliott 

Trinoclodus perplenus EllioH 



Thy 



oporello silvestrn Pfender 



CRETACEOUS 



-TbTTT; 



Fig. 6. Stratigraphic ranges of dasyclad algae in the Middle East. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 85 

ranges of 29 dasyclads listed by him with the 45 now shown for the same time- 
interval in fig. 6. A general correspondence of restricted ranges, with individual, 
local differences, may be observed. 

Permian 

The dasycladaceae recognized from the Iraqi Permian and their distribution there- 
in are shown in Fig. 7. This Permian succession is approximately 800 m. thick, and 
was sampled by Wetzel and others through complete successions near the localities 
of Ora and Harur, in the north of Mosul Liwa, near the Turkish frontier. The 
general succession is set out in Dunnington, Wetzel and Morton (1959) where the 
whole series of thick upper and lower limestone divisions, separated by a thinner 
evaporitic development, is named the Chia Zairi Formation ; Hudson (1958) has 
named the two thick limestone divisions, so that the succession, from bottom to top, 
comprises Zinnar Formation, Satina Evaporite Formation and Darari Formation. 

The Zinnar rests unconformably on Carboniferous (Tournaisian) . The Darari, at 
its top, shows evidence of progressive shallowing, though the actual contact with the 
overlying Triassic is said to be abrupt. 

Of the rich faunas collected, only two, both from the Zinnar, have been adequately 
investigated. A coral fauna, from the Wentzelella limestones at about the middle of 
the Zinnar, was compared by Hudson (1958) with similar faunas elsewhere in Asia, 
the latter often including Neoschwagerina, especially N. cratulifera (Schwager) 
" which could quite well be the age of the Wentzelella-Limestones of Iraq ". This 
would be Artinskian-Kungurian (or Leonard- Word) . A fusulinid-fauna occurs near 
the base of the Zinnar : this was studied by Lloyd (1963) who thought it " some- 
what older " than a comparable Iranian assemblage dated as of Parafusulina-zone 
age i.e. a possible Sakhmarian-Artinskian (Wolfcamp-Leonard) age for this lower 
part. 

No other detailed faunal evidence for age is at present available above these levels, 
though the upper Darari is similar to the north Italian Bellerophon-limestone 
described by Accordi (1956). It may be that sedimentation was more or less 
continuous throughout, up to the Triassic contact, and that the Zinnar-Satina- 
Darari correspond to PSakhmarian (part), Artinskian-Kungurian-Tartarian, but this 
remains to be proved by detailed analysis of the faunas. It is unlikely that the 
boundaries of the Satina will correspond with stage levels. Against this lack of 
detail the ranges of the dasyclads are of some interest. 

Mizzia velebitana ranges from near the base of the Iraqi Permian to near the top, 
accompanied by the nondasyclads Gymnocodium bellerophontis and some Permo- 
calctdus spp. The other dasyclads have very different ranges. Anthracoporella 
mercurii is confined to the basal beds of the Zinnar : Pseudoepimastopora ampullacea 
occurs in the Zinnar only, as do the non-dasyclad Ungdarella Maslov and the new 
Permoperplexella. Atradyliopsis darariensis occurs only near the top of the Darari, 
and Pseudovermiporella sodalica only within this formation. " Clypeina sp. " 
marks the emergent conditions of the Zinnar-Satina contact level. 

It is probable that a fresh sampling, carried out primarily for the collection of 



86 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



algae, would add much to our knowledge of these fine sections and of the Permian in 
general, and possibly permit an algal zonation, from dasycladaceae and other families, 
of potentially wide application in Asia. 



Met res 

O— i 



lOO- 



2O0 — 



300 — 



400— 



500 — 



600 — 



700 — 



ORA 



800— I .• S 

■' y 

^(CARB.) 

Fig. 7. The Permian dasyclads of Iraqi Kurdistan at Ora and Harur, Mosul Liwa. 
1. Anthracoporella mercurii Elliott. 2. Atractyliopsis darariensis Elliott. 3. " Clypeina " 
sp. 4. Mizzia velebitana Schubert. 5. Permoperplexella attenuata Elliott. 6. Pseudo- 
epimastopora ampullacea Elliott. 7. Pseudovermiporella sodalica Elliott. 



(TRIASSIC) 



DARARI 
FORM 



SATINA 
FORM 



ZINNAR 
FORM 



isf ''o 



HARUR 



calcareous algae of the middle east 87 

Lower Jurassic 
The occurrence of the Liassic Palaeodasycladus in the Lower Musandam of Oman is 
compatible with the age from other evidence (Hudson & Chatton 1959), but as the 
alga is so far recorded only from one level it shows no more than as an easterly 
occurrence of this well-known Mediterranean fossil. 

Upper Jurassic-Lower Cretaceous 

The ranges of various dasyclads in the Middle East at these levels are shown on the 
chart. Reference to the European literature indicates different local ranges for some 
of these species. Thus Actinoporella podolica is Portlandian at the Galician type- 
locality, Portlandian-Valanginian in Switzerland, Portlandian-Hauterivian in Italy, 
and Valanginian-Aptian in the Middle East. This probably reflects facies-preference 
along successive Tethyan coasts, partly obscured by some occurrences being pre- 
served in off-shore debris-facies. It is of course possible that a suite of similarly 
well-preserved specimens from each locality would permit successional subdivision 
of the species. The type-material comprises loose, dissociated verticils, whereas 
most of the other records are from random thin-section material. However, this 
must await future studies. In association with other microfossils, A. podolica is a 
useful species in the Middle East, as are most dasyclad remains. Munieria baconica 
shows a somewhat similar range, with varying local occurrences. By contrast, such 
species as Clypeina lucasi and C. marteli occur only at the same level in Oman as 
that of the Algerian types. The European ranges of a dasyclad species, and the 
details of its Middle East occurrences, will already have been noted under each 
species-description. 

The algal dating of the Jurassic-Cretaceous contact in the wholly marine Tethyan 
succession is of some importance. Over large type-areas of western Europe a varying 
thickness of nonmarine Purbeck-facies strata occurs between undoubted marine 
Upper Jurassic and Lower Cretaceous. This Purbeckian is conventionally assigned 
to the Jurassic, though the studies of Donze (1958b) on the Jura area, and Casey 
(1963) on England, suggest that much of it is Cretaceous (see also Bartenstein, 1965). 
In southern France, where marine Tithonian is succeeded by marine Berriasian, the 
two may be distinguished by their ammonite faunas. In many other Tethyan lime- 
stone successions at this level the absence of ammonites, whether due to their non- 
occurrence in the fauna or their non-availability as in samples from bore-holes, 
necessitates estimation of the junction from microfossils in thin-section. The for- 
aminifera give no clear picture, and tintinnids are confined to a special stratigraphical 
facies. Dasyclad algae are often abundant ; in my experience, if determined 
carefully, with a full knowledge of their recorded ranges elsewhere and used in 
conjunction with non-dasyclad algae such as Permocalculus spp. and various non- 
algal fossils such as the hydrozoan Cladocoropsis, it is usually possible to give an 
accurate age-determination. 

Upper Cretaceous 
The dasyclads of the Middle East Upper Cretaceous are fewer in number than those 



88 CALCAREOUS ALGAE OF THE MIDDLE EAST 

of the Lower Cretaceous. The most important florules are the Trinocladus tripoli- 
tanas assemblage of about Turonian age, common to North Africa, Iraq, Trucial 
Oman and perhaps elsewhere, and the Maestrichtian assemblage of which Cymopolia 
tibetica also occurs in the Himalayas. 

Palaeocene-Lower Eocene 

The rich dasyclad flora of Kurdistan and elsewhere occurs throughout the Pala- 
eocene and Lower Eocene. In Kurdistan it has been possible to date the two stages 
foraminiferally in certain sections e.g. at Kashti, also at Sinjar and Koi Sanjak (Van 
Bellen 1959) and unpublished reports. The algae show no consistent stratigraphical 
differentiation throughout, though there is a sharp change from the Cretaceous below 
and to the Middle Eocene above. This flora contains elements known from the 
Indian " Danian " of the Trichinopoly coast (recently correlated on foraminiferal and 
other evidence with the Lower Palaeocene elsewhere : Sastry & Rao 1964, Rajago- 
palan 1965) and from the European Montian, and it appears that algally at any rate 
the Palaeocene commences with the immediate post-Maestrichtian, which is also the 
opinion of some workers on foraminifera (e.g. Berggren 1964). In this connection it 
should however be noted that the Tethyan Danian-equivalent (if and when present) 
may not easily be recognizable by comparison with the northern European type- 
development. 



v. the geographical distribution of tethyan algae 

The most casual student of Tethyan fossils is struck by the very wide east-west 
distribution of Tethyan fades and fossils, which occur in disconnected outcrops over 
enormous distances : there is often more difference between the south of England 
and the south of France at the same level than correspondingly between Spain and 
the Middle East, India or even Borneo. The algae are no exception to this : in the 
Permian Mizzia velebitana and the non-dasyclad Gymnocodium bellerophontis have a 
world-wide latitudinal distribution, and in the Cretaceous Neomeris cretacea occurs 
in both Mexico and the Middle East. The Liassic Palaeodasycladus ranges from 
Algeria to Iran, and the Upper Jurassic algal suite from France and Switzerland to 
the Persian Gulf, while Terquemella is found in the Palaeocene-Eocene of Central 
America, Europe, the Middle East and India. It is true that there are curious 
absences and near-absences from the collections studied, e.g. the Jugoslav Permian 
Velebitella (also known from Turkey, Giivenc 1965) and the Italian Cretaceous 
Triploporella spp., both of which one would expect to find conspicuously at the 
appropriate levels, but future collecting may well remedy this. 

With this wide marginal-Tethyan distribution of the same or closely-related 
species it is difficult at most levels to detect evidence of directional migration. The 
Palaeocene-Lower Eocene of the Middle East, however, shows an apparent mingling 
of eastern and western elements. Indopolia and Dissocladella from the east are 
there, associated with Cymopolia from the west. These eastern and western forms 
quoted are otherwise mutually exclusive at this level to India-Pakistan and Europe, 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



89 




Polaeocene Algae of the Middle East; 
Pan — Tethyan and Local types. 



Approximafe Tethyan Margin 

D Broeckella 1 

O Clypeina > Pan - Tethyan 

l\ Terquemella J 

I Furcoporella 

W Pogodaporella 

▼ Thyrsoporello silvestf 

^ Tnnocladus perpleiiu 



Fig. 8. 




Palaeocene Algae of the Middle East; 
Eastern and Western types. 



Fig. 9. 



Approximate Tethyan Morgin 

■ O.ijoclodella sayitriae | 

9 Indopolia 

O Cymopolia Wi 



<JO 



CALCAREOUS ALGAE OF THE MIDDLE EAST 




Cymopolia; Upper Cretaceous 
and Palaeogene occurrences 
demonstrating Tethyan dispersal. 



. Approximate Tethyan Margin 

9 Upper Cretaceous 

(Maestfichtion) occurrence! 
\J Palaeogene occurrence! 



Fig. io. 




Cymopolia; Neogene and living 
occurrences to show Tethyan 
origin of relict distribution. 



Appr< 



lie Tethyan Morgir 



U Neogei 

9 Recent occurrence* 



gene occurrtnces 



Fig. ii. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



9i 




Trinocladus, an extinct dasyclad; 
distribution showing relict — 
occurrence in the Palaeocene. 



Approximate Telhyon Margin 

XJ Trmoclodus Spp 

_ (Upper Cretaceous) 

^P Trinocladus perplexus 

(Palaeocene _ Lr. Eocene) 



Fig. 12. 




Thyrsoporella, an extinct dasyclad ; 
distribution showing post-Palaeocene 
dispersal. 



Approximate Tethyon Morgir 

JQl Th/rsoporeila 

, (Palaeocene — Lr. Eocene] 

/\ Thyrjoporella 
(M. Eocenel 



Fig. 13. 



9-2 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



but Broeckella, Clypeina and Terquemella occur in both as well as in the Middle East, 
and Pagodaporella is so far known only from the Middle East. This assortment of 
genera in the very sector of the Tethys which in mid-Tertiary was to become the land 
barrier dividing the marine Mediterranean-Antilles from the Indo-Pacific is no doubt 
significant for the modern discontinuous distribution of dasyclads, even if most of the 
genera quoted are now extinct. The distribution-maps (Figs. 8-14) illustrate 
different aspects of past and present dasyclad occurrences. The value of these dated 
fossil occurrences may be seen by a comparison with the distribution-maps of 
Svedelius (1924) which, whilst taking account of former continuous sea-ways, show 
only Recent distribution. 

The work of Kaever (1965), on the micropalaeontology of Afghanistan, contains 
numerous records of Tethyan algal species familiar in the Middle East. Unfor- 
tunately this paper came too late to my notice for inclusion of the detailed species 
records. 

VI. ECOLOGY 

At the present day dasyclads are a relatively inconspicuous element in marine 
algal floras. Although life has sometimes taken me to warm-water shores, I have 
never seen or collected living dasyclads. Their ecology has been briefly summarized 
by Pia (1920), Cloud (1962) and Johnson (1961b), all palaeontologists, for comparison 
with fossil occurrences. They occur in warm shallow coastal waters in sheltered 
situations in tropical and subtropical seas, and in areas marginal to the latter, such as 
the Mediterranean. Their maximum abundance is said to be from low-tide level to 
5-6 m. depth, extending down in diminishing abundance to 10 m., and with scattered 
occurrences below this to 30 m. or more, depending on intensity of illumination and 




Distribution of the Polaeocene 
Pagodaporella, and its possible 
living descendant Dosyclodus. 



Approximate Telhyan Margin 

■ Pagodaporella (Polaeocene) 
Q Dosyclodol (Recent] 



Fig. 14. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 93 

clearness of water. However Edelstein (1964) records Dasycladus vermicularis 
(Scop.) Krasser in the eastern Mediterranean from 18-90 m., represented by well- 
grown individuals larger than those in the littoral flora ; it seems clear that inferences 
as to exact water-depths should not be drawn from fossil dasyclads alone. The 
sheltered parts of coastal bays and some lagoons are favoured habitats, and they are 
tolerant of the reduced salinities which may occur there. Probably, like most non- 
stenohaline marine organisms, they are euryhaline and have a limited tolerance for 
temporary conditions of increased salinity. Such general conditions are associated 
geologically with regions of uplift, and the fossil dasyclad record confirms this. As 
with most marine organisms they have a scattered distribution outside the optimum 
habitat, and Chapman (1961 : 104, 106) gives records of Neomeris on mangrove roots 
and a stunted population of Batophora in an exposed situation. 

Konishi & Epis (1962) gave a distribution-map showing clearly the restriction of 
living Neomeris spp. to areas within the marine isocrymes for 20 °C, and a table giving 
bathymetric occurrences. They discussed the implications of this evidence for the 
fossil occurrences, concluding that the fossil species probably occupied similar warm- 
water environments, then more widely-spread, as is generally accepted (e.g. Davis & 
Elliott 1957 : 269). 

So far as can be deduced from associated fossils and the nature of the rock, the 
extinct dasyclad floras of the Middle East (and elsewhere) favoured exactly similar 
environments in the past to those now favoured by their descendants. However, at 
times of maximum abundance, dissociated debris of calcareous dasyclad origin forms 
a conspicuous element in sediments deposited further out to sea, for which the term 
" debris-facies " was introduced (Elliott 1958a). 

In the Permian succession of northern Iraq the dasyclad Mizzia velebitana is 
abundant at many horizons through most of a thickness of over 800 m. It is 
accompanied throughout by profuse remains of Gymnocodium bellerophontis and 
various species of Permocalculus. These Gymnocodiaceae have been variously 
interpreted (Pia 1937 ; Elliott 1955a ; Konishi 1961) as Codiaceae (Chlorophyceae) 
or Chaetangiaceae (Rhodophyceae) ; whatever the taxonomic position, both the 
families cited are quiet-water marine algae today as compared with the reef-forming 
melobesioids. It is significant that amongst all the Iraq Permian algae there occurs 
only one solenoporoid, a group supposedly ancestral to the melobesioids (Elliott 
1965a) and similarly of reef and shoal facies, and that uncommonly ; Solenopora 
centurionis Pia. The Mizzia-Gymnocodium association, sporadically abundant in the 
lower or Zinnar Formation, disappears within the lowest beds of the median Satina 
Evaporite, along with other algae and almost all fossils, but reappears in the upper- 
most beds, and so into and through the Upper or Darari Formation. At the top this 
latter shows signs of transition to the overlying but unconformable Lower Triassic, 
which is in the Werfenian alpine facies without remains of algae. 

The Iraqi Permian contains some beds with a predominantly coral, brachiopod or 
crinoid fauna (Hudson 1958 ; Dunnington, Wetzel & Morton 1959). Moreover, in 
some of the algal beds the coarse colander-pore Mizzia- segments are worn, indicating 
post-mortem drifting from the position of growth. But the algal beds are suffi- 



94 CALCAREOUS ALGAE OF THE MIDDLE EAST 

ciently numerous to prove the continued growth of Mizzia and other dasyclads in 
coastal environments throughout the whole period of deposition, even though the 
sediments at the sampled successions of Harur and Ora reflect the intermittent 
shifting of this coastline. The minor dasyclad elements, Anthracoporella, Atradyli- 
opsis, Clypeina, Permoperplexella, Pseudoepimastopora and Pseudoverniiporella do not 
in any way conflict with the picture drawn from the dominant Mizzia. The very 
scarce Clypeina occurs at the top of the Zinnar and the bottom of the Satina Evapor- 
ite, a fact consonant with later opinions on the facies behaviour of the Mesozoic 
species. 

Rezak (1959) dealing with the Saudi Arabian Permian, observed the occurrence- 
relationships and associations of Epimastopora, Gymnocodium and Mizzia, and 
suggested a possible algal depth zonation as explanation. In Iraq Pseudoepimasto- 
pora is confined to the lowest division, the Zinnar Formation, in which particularly 
well-marked coral and brachiopod beds occur and in which the Gymnocodium- 
Mizzia beds are more sporadic than in the later beds. From the sampling available 
to me, I cannot interpret my records along the lines of Rezak's suggestion, but such 
depth-zonation may well have existed. 

The rarity of Triassic dasyclads in the Middle East has already been noted ; it 
forms a remarkable contrast to the diplopore-limestone of alpine Europe. The 
evidence of the Kurdistan Geli Khana and Kurra Chine formations (Middle and 
Upper Trias) suggests originally unfavourable conditions. 

Two Jurassic algal occurrences give a clear picture of the original ecology. The 
Palaeodasycladus-bed in the Liassic portion of the Musandam Formation in peninsular 
Oman, Arabia, shows a limestone, now partially dolomitized, crowded with healthy, 
full-grown specimens of well-developed P. mediterraneus, whole and broken. Asso- 
ciated are concentric nodules of probable cyanophyte algal origin. The picture is of 
an extensive spread of the dasyclads in clear, shallow warm water, on a limy bottom : 
a typical habitat. 

In the Upper Jurassic of Qatar and elsewhere in the Persian Gulf area the " Arab 
zone " (Kimmeridgian-Tithonian) yields a florule of Clypeina jurassica, Salpingopor- 
ella annulata and Cylindroporella arabica occurring in fine-grained and oolitic lime- 
stones : associated are numerous crustacean coproliths, Favreina salevensis (Pare^as), 
and small gastropods and foraminifera. The picture is again of shallow, clear limy- 
bottomed waters, possibly lagoonal or enclosed ; the snails and crustacean traces 
may be indirect evidence of an abundant growth of non-calcarous green algae of 
which nothing certain now remains. The modern eel-grass beds of the West Indies 
and Bahamas would be comparable : Chapman (1961 : 9) gave a Jamaican record 
of numerous Codiaceae and Dasycladus sp. from this environment. 

In the same general area of southeastern Arabia a very different picture is given by 
the Lower Cretaceous algal beds penetrated in the Fahud no. 1 boring. Here the 
rock is formed of rounded pieces of the crusting problematic algae Lithocodium and 
Pycnoporidium, with similar-sized pieces of stromatoporoids and less frequent coral, 
and rare valves of cemented thecidean brachiopods. Associated are numerous 
examples of segments of the dasyclad Cylindroporella sugdeni. This is reef or shoal 



CALCAREOUS ALGAE OF THE MIDDLE EAST 95 

debris, current-swept and well-rounded, and washed out some distance from the 
organic growths which furnished it, even if to no great depth. The Cylindroporella, 
a plant believed to be possibly somewhat similar in form to the living segmented 
Cymopolia, owes its preservation to the relatively large, stumpy, well-calcified 
segments surviving transport : the plants themselves would have grown on the lee 
side of the shoals. 

In the Iraqi Cretaceous, from the base up to Albian level, dasyclad remains are not 
uncommon and sometimes abundant. The principal genera involved are Actino- 
porella, Cylindroporella, Munieria and Salpingoporella ; Acicularia, Acroporella, 
Clypeina, Pianella and Triploporella also occur. The commonest non-dasyclad alga 
is Permocalculus (see Elliott 1960 for full algal lists). Complete or near-complete 
fossils, whether tubes, segments or verticils, are relatively uncommon and usually 
occur in a fragmentary condition, in limy marls and argillaceous limestones. This, 
the " debris-facies ", has been described by me (Elliott 1958a), where I interpreted it 
as off-shore sedimentation in which fragments of littoral calcareous algae were 
sedimented out at sea with inorganic grains of smaller size and higher specific 
gravity. A comparison was made with modern sediments around Pacific atolls, 
where fragmentary Halimeda and large foraminifera, roughly comparable with the 
Cretaceous Permocalculus and Orbitolina respectively, are washed out to sea. No 
exact analogy proved possible : the very extensive Cretaceous deposits were formed 
on inter-orogenic shelf-seas then more widely developed than with today's post- 
glacial submarine topography, and the wealth of Cretaceous littoral green algae 
proliferated before the maximum, later development in the Tertiary and present-day 
of reef-forming melobesioid algae. This debris-facies is very characteristic in the 
Middle East, and is most typical of the Lower Cretaceous, though known elsewhere 
from the Upper Jurassic. It occurs much more widely than remains of the littoral 
deposits where the algal material originated. 

A completely different facies prevailed in the Upper Cretaceous of Northern Iraq. 
Here massive limestones, of reef or shoal and fore-reef facies, with abundant rudist 
remains, show the largely recrystallized remains of the dasyclad genera Neomeris 
and Cymopolia. Presumably these dasyclads grew in quiet situations on and around 
the reefs and rudist banks. In the Maestrichtian this limestone development 
tongues eastwards into a clastic facies (transition of Aqra Limestones into Tanjero 
Formation). As is usual with reef-structures, diagenesis has been active within the 
main calcareous mass and the best fossils occur at the junction, as with the German 
Upper Jurassic calcisponge and coral reefs, and the Kurdistan Maestrichtian dasyclad 
Cymopolia anadyomenea was described from this well-preserved marginal material. 
Within the Tanjero itself two fragmentary algae occur not infrequently ; the dasy- 
clad Trinocladus radoicicae and the codiacid Ovulites delicatula, represented respec- 
tively by rare broken tubes and not uncommon bead-like segments. These are 
remains of littoral algae, sedimented not far off-shore with the sand-grains, and very 
similar to, say, the codiacid Penicillus and the dasyclad Batophora in the Recent 
Bahamas (Newell et al., 1959 : 224). 

Finally, the environments of the Palaeocene Dasycladaceae must be considered. 



96 CALCAREOUS ALGAE OF THE MIDDLE EAST 

In Iraqi Kurdistan the fossils occur in two principal intergrading formations of the 
same age. These are the Sinjar limestones and marls, with a rich and varied dasy- 
clad and other algal flora, and the Kolosh elastics, a coarse green-rock sand with a 
much more restricted flora of which only two species, only one a dasyclad, are 
common. Van Bellen (1959) considered the Sinjar as marking the reef-like facies of 
the Palaeocene (and Lower Eocene), which occurred to seaward of the near-shore 
Kolosh accumulation-zone of clastic detritus from the land. The Sinjar reefs and 
shoals did not form a continuous barrier, but a broken line of separate reef-banks and 
islands, sometimes backed by developments of the lagoonal Khurmala Formation, 
whose altered deposits sometimes contain indeterminate algal debris. 

The Kolosh has yielded occasional examples of such dasyclads as Cymopolia and 
Dissocladella, and the codiacid Halimeda, etc., but the only common algae are the 
dasyclad Trinocladus perplexus and the codiacid Ovulites morelleti. These are 
presumably the descendants of the species-pair of the same genera recorded above 
for the lithologically similar underlying Cretaceous Tanjero, but they are much more 
abundant in the succeeding Kolosh. Presumably they were littoral algae from the 
coast : some indirect support for this is found in the complete absence of Trinocladus 
from the Sinjar, although Ovulites is common there. I would suggest this as possibly 
evidence that Trinocladus for some reason only grew along the coast, whence its 
broken tubes were wafted into the sandy offshore sedimentation, and that Sinjar 
shoal-conditions were unfavourable to it. By inference, the bulk of Kolosh fossils of 
Ovulites came likewise from the coastal population, and only a minority from the 
Sinjar shoals : no more in fact than the odd Kolosh Cymopolia etc. (unless indeed 
these came from a minority population on the coast). 

Possibly Trinocladus perplexus was restricted to littoral waters with fresh-water 
dilution from the land drainage : Teredo-bored wood is not uncommon in the Kolosh 
Formation (Elliott 1963b), and this is a familiar indication of adjacent coastal or 
estuarine conditions, as in the English Lower Eocene London Clay. 

The richer Sinjar flora seems to have been buried where it lived, more or less, 
amongst the pockets, pools and channels of the shoal and reef belt. Sedimentation 
here was more varied and irregular, and fossils are sporadically more abundant. In 
submerged channels and on submerged shoals, and in sheltered waters between and 
to the landward of the barrier-components, the dasyclads found conditions congenial 
to them : they are often very well-preserved and seem to have been buried where 
they grew, although rolled and broken material is also not uncommon. In these 
happy conditions a considerable variety of algae grew together : the last abundance 
of endospore dasyclads (Trinocladus, Dissocladella, Thyr sopor ella) and the rare 
Broeckella co-existing with choristospore genera (Indopolia, Cymopolia), together 
with Clypeina and the more problematic Fur copor ella. Codiaceae were represented 
by abundant Ovulites, an extinct relation of the modern Penicillus, and by Halimeda, 
not yet swamping the flora. But also in the Sinjar environment was a rich variety 
of calcareous red algae : melobesioids such as Archaeolithothamnium spp., Litho- 
phyllum, Mesophyllum, Lithothamnium and Lithoporella, with surviving soleno- 
poroids (Parachaetetes and Solenomeris) , and the problematic Pseudolithothamnium 



CALCAREOUS ALGAE OF THE MIDDLE EAST 97 

and Distichoplax. Most of these were nodular or crusting forms, forming an 
appreciable volume of the actual reef-structures and plastering the reef-fronts in the 
surf zone. These two different environments, favoured by the green and red algae 
respectively, are strikingly demonstrated by an analysis of Palaeocene-Lower 
Eocene algae from Iraqi Kurdistan. Of 92 samples selected as showing well- 
preserved algae, from localities all along the mountain arc from Banik in the north to 
Sirwan-Balambo in the east, 67% show green algae only, 29% red algae only, and 
only 4% a mixture of the two. Moreover, in the mixed samples one or other group 
was a worn minority in each case. The preponderance of green-algal, back-reef 
samples is perhaps to be explained by the inclusion of samples from intertonguing 
Kolosh Formation, where only green algae occur, but there is no doubt in which 
environment any particular sample originated. At some localities, e.g. Sirwan- 
Balambo, red and green algal samples alternate, reflecting the former shifting reef 
and shoal pattern through time at the spot now arbitrarily revealed as a cliff-section ; 
at others, e.g. Koi Sanjak and Kashti, green and red algae predominate respectively. 
These differences reflect local aspects of a palaeogeography not known in detail, but 
emphasize the mutual exclusiveness of the two environments. 

In southwestern Iraq the desert outcrops of the Palaeocene Umm er Rhudhama 
Formation reveal a different picture. This was a more gently-sloping, non-orogenic 
shore of the Tethys than the opposite coast described above for Kurdistan : the 
sea extended as a shallow sheet of water on to the slopes of the Arabian landmass, 
and sedimentation was slow. The algae are abundant ; although abominably ill- 
preserved, almost all are dasyclads, and there are no red algae at all. This was a 
shallow-water coast with frequent sheltered bays with limy bottoms on which 
spreads and thickets of dasyclads proliferated : it is a much less rich flora than that 
of Kurdistan, and presumably provided few micro-environments like those of the 
Kurdistan shoal-belt. 

Summarizing, with Dasycladaceae especially in mind, the principal kinds of 
marine algal associations in the Middle East Tethyan rocks examined indicate : 

1. Reef and shoal environments, mostly exposed to rough surface water, or tide- 
or current-swept. The home of nodular or crusting algae (Solenoporaceae, Coral- 
linaceae and the problematic Lithocodium) , with dasyclads extremely rare. 

2. Fore-reef or seaward shoal-slope deposits. Much debris from the environ- 
ments of category 1, as well as some indigenous non-dasycladacean algae, and only 
exceptionally dasyclad debris from elsewhere, depending on current-patterns and 
sediment-transport . 

3. Calm lagoonal waters behind reefs and similar barriers. Abundant Dasy- 
cladaceae and Codiaceae, few other calcareous algae, with burial on the site of 
growth, and only exceptionally current-transport to category 2. 

4. Calm coastal bays and similar shallow, largely land-locked waters. Dasy- 
cladaceae and Codiaceae as in category 3. Burial on the site of growth, occasional 
current transport to category 2, and much contribution to category 5. 

5. Neritic deposits out to sea on coastal shelves. Much sedimentation of broken 
littoral and sublittoral algal skeletal remains, largely dasycladacean, as a con- 



98 CALCAREOUS ALGAE OF THE MIDDLE EAST 

spicuous minority-constituent of calcareous muds. This is the " debris-facies " 
(Elliott 1958a). 

It must be emphasized that some of the local rock-facies encountered are not 
easily recognizable in terms of the environments set out above. Diagenesis has 
sometimes obscured or obliterated part of the evidence, but above all knowledge of 
the small-scale lateral facies-changes is insufficient for full interpretation of the 
ecology of the fossil-assemblages seen in hand-specimens. The original surveys were 
stratigraphical and structural in intent, and only much later were the algae recog- 
nized by me in thin-sections and hand-specimens of others' collecting, and then put 
aside for this and other studies. 

The Middle East dasyclad environments reconstructed above are varied in time 
and space, and in the nature of the rocks which now entomb the fossil evidence. 
But it is noteworthy that none have yielded any evidence to suggest to me that the 
ecological requirements of the dasyclads of the past were essentially different to those 
of their living descendants. 

VII. THE EVOLUTION OF THE DASYCLADACEAE 

From the introductory account given above, it will be remembered that the 
collection of dasyclads from the Middle East which forms the subject of this work 
was selected from material collected for general stratigraphical purposes. Excep- 
tionally it proved rich in species for palaeobotanical study, but much of it yielded 
only sufficient evidence for identification and age-correlation with species previously 
described elsewhere. Nevertheless, so much material, dasyclad remains from an 
Upper Palaeozoic to Lower Tertiary timespan in a mid-Tethyan area favourable to 
them, inevitably invites the question as to whether any further light is thrown on 
the evolution of the family as a whole. 

It may be said at once that nothing emerges seriously to modify the general 
picture of dasyclad evolution sketched by Julius Pia (Pia, see bibliography of : see 
also Rezak 1959c). The dasyclads, having achieved the verticillate branch-pattern 
in the Palaeozoic, proceeded to progressive and varied elaboration of the side- 
branches, and to the progressive shift of the reproductive structures from within the 
primitive thick stem-cell, into swollen lateral branches, and finally into special 
structures borne on the laterals, or into the specialized reproductive discs charac- 
teristic of some genera. The reproductive structures themselves are disappointing : 
they yield no reasonable evidence of sexual mechanisms as have the fossil Melo- 
besioids (e.g. M. Lemoine 1961), or the Chaetangiaceae (Elliott 1961). Presumably 
the dasyclad reproductive bodies known conventionally in the fossils as sporangia, 
were similar to those of most Recent genera and so contained resting cysts from which 
gametes were only set free after shedding : this arose as a necessary consequence of 
the well-developed calcification around these organs. Release of the reproductive 
elements thus became only possible after the break-up of the calcified layers, and 
calcification is usually well-developed around the sporangia. The living Dasycladus 
with restricted stem-cell calcification only, is exceptional in shedding its gametes 
direct. This condition was regarded by Pia as secondary, Dasycladus thus bearing 



CALCAREOUS ALGAE OF THE MIDDLE EAST 99 

no more direct relation to the ancestral non-calcified proto-Dasyclad than a naked 
slug has to the unshelled proto-gastropod. If this is so, and if the present writer's 
analysis of Pagodaporella is correct, then this condition had arisen by the beginning 
of the Tertiary, but was and is uncommon. 

If the fossil sporangia are intrinsically uninteresting, their progressive evolutionary 
movement within the dasyclad plant, from endospore to cladospore to choristospore, 
is the most persistent trend in dasyclad evolution. In the genera studied, an endo- 
spore genus (Atractyliopsis) occurs in the Permian, where it is accompanied by 
cladospore genera. Cladospore genera predominate in the Mesozoic and survive to 
the Palaeocene, where they are represented by such genera as Trinocladus and 
Thyrsoporella, and Broeckella. Choristospore types of conventional pattern appear 
in the Cretaceous (e.g. Cymopolia, which also shows a species intermediate in this 
character) and are dominant today. In Recent genera with terminal reproductive 
discs these structures are regarded (Fritsch 1935 : 397 ; Egerod 1952 : 341) as 
homologous with reproductive structures borne laterally on the primary branches of 
choristospore dasyclads e.g. Bornetella. If the extinct Clypeina is grouped with 
Acetabularia and Acicularia, as suggested by various workers (see above p. 28), then 
this specialized condition, expressed in Clypeina as serial fertile whorls rather than as 
a single terminal disc, arose possibly in the Permian, certainly in the Triassic. That 
is, it arose at the same time as, or later than, the change from endospore to cladospore 
and before the evolution of the choristospore type proper so far as is known. This 
suggests that the serial reproductive discs of Clypeina are homologous with the 
swollen branches of cladospore genera, and that the genus (? Permian, Triassic- 
Oligocene) is thus an earlier, different, achievement of this structure than the 
Acetabulareae (? Jurassic, Cretaceous-Recent) show. It is noteworthy that the 
radial tubules of Clypeina spp. do not show the calcified sporangial contents in fossils 
as do those of Acicularia ; that is they correspond in this respect to the normal 
swollen branches of cladospore genera, which only exceptionally display this condi- 
tion e.g. Triploporella. Moreover, Clypeina became extinct in the Tertiary as did 
other cladospore genera, while the living dasyclad flora, of choristospore genera, 
includes Acetabularia and Acicularia. It seems likely, therefore, that the discs of 
Clypeina represent an earlier development in time of the condition seen in Acetabu- 
laria, morphologically similar but of dissimilar origin ; this is a not uncommon 
phenomenon in evolution. Clypeina is therefore placed in the new tribe Clypeineae, 
to include forms with reproductive discs considered to be of cladospore origin. 

From a strictly morphological point of view, the relegation of Actinoporella to the 
synonymy of the earlier-proposed Clypeina, now known to contain a small minority 
of stellate species somewhat like Actinoporella, is a logical proposal. However, the 
earliest stellate Clypeina, the Valanginian C. marteli Emberger, is one of a group of 
varied species appearing after the disappearance of the Upper Jurassic C. jurassica, 
and presumably evolved from it at the time of the terminal Jurassic uplifts and 
lagunal developments. Actinoporella itself co-existed in the Upper Jurassic with C. 
jurassica. Pia's suggestion (1927 : 693) that Clypeina arose direct from Actino- 
porella must await understanding of the Permian Clypeina, and possible new 



ioo CALCAREOUS ALGAE OF THE MIDDLE EAST 

Mesozoic records. His interpretation of Adinoporella as similar to the Triassic 
Oligoporella but differently calcined is followed here : Adinoporella is regarded as a 
valid genus and left in the Diploporeae. 

These problems apart, the evolutionary change in position of dasyclad reproductive 
structures is the most significant feature of their long history. It has been written 
(Elliott 1962) "we do not clearly know the special advantage of choristosporic 
structures, whether a direct one in shedding reproductive elements more easily, or 
an indirect one in their being produced more freely and lavishly with no greater or 
even less strain on the metabolism of the plant, but although not properly understood 
it is a main trend in dasyclad evolution ". 

Although no precise elucidation of this point can be offered here, the trend itself, 
clearly indicated by Pia (1920), has been confirmed by subsequent work including the 
present study. Whatever its significance, it has not saved the Dasycladaceae from 
decline to a very subordinate position indeed in modern marine floras. Although 
growths of living dasyclads sometimes form extensive patches or thickets on the 
sea-floor, I know of no existing deposit in which a great thickness of sediment 
consisting principally of their calcareous tubes is being accumulated. A prolonged 
and persistent dense growth of dasyclads to build up considerable thicknesses of 
dasyclad limestones as are known from the Alpine Trias, e.g. the Essino Limestone 
of northern Italy, is apparently a thing of the past. Pia (1920 : 187) attributed this 
decline of the dasyclads principally to the development and spread of the articulated 
Corallinaceae, with different cellular organization, from the Cretaceous onwards. 
Much of this spread was into environments for which the dasyclads were not suited, 
by reason either of the mechanical effects of water movement or of lower tempera- 
tures. The appropriate modern ecological analogue comes from a related family of 
green algae, the Codiaceae, where Halinteda occurs in dense growths, notably in the 
lagoons of atolls and other back-reef environments once largely colonized by dasy- 
clads. Calcified segments from generation after generation of plants pack down to 
form true ##^'m^a-limestones, well evidenced by borings into the reefs of these 





Fig. 15. Diagrammatic vertical sections of comparable portions of the dasyclad Cymopolia 
(left) and the codiacean Halimeda (right). Plant tissue stippled, calcareous structure 
black. To show the encased dasyclad sporangia and free codiacean reproductive growth. 
Greatly enlarged. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 101 

islands, and by many records of Halimeda-limestones in the Tertiary of tropical and 
subtropical latitudes. Since Halimeda is quite heavily calcified, it is not calcification 
itself which has impeded the spread of dasyclads amongst more numerous non- 
calcified green algae in suitable environments. The explanation probably lies in the 
reproductive mechanism : Halimeda sheds abundant gametes freely from special 
deciduous non-calcified outgrowths from the segments. In almost all dasyclads the 
release of the resting cysts depends on eventual break-up of the calcareous structures. 
The reproductive bodies of Halimeda are almost unknown in a fossil state, a unique 
occurrence being recorded by Pfender (1940 : 245), whereas those of dasyclads 
survive unbroken in a majority of the specimens found fossil. There is some evidence 
which has been interpreted as indicating that Halimeda was of hybrid codiacean 
origin in the late Cretaceous (Elliott 1965b) ; certainly its spread and abundance in 
the Tertiary and at the present day is remarkable. For all their morphological 
elaboration, the dasyclads did not overcome the initial handicap inherent in the 
calcification of the reproductive bodies ; this in turn springs indirectly from the basic 
morphology of laterally whorled stem-cell, the Codiaceae by contrast being formed 
of richly-branched, agglomerated threads with largely marginal calcification between 
these and not encasing them, at any rate in the actively growing segments. There is 
some similarity with marine invertebrate evolution, where, amongst the brachiopods, 
progressive evolution of very complicated calcareous supports for the fleshy lopho- 
phore did not compensate for the basic inferiority of this organ when compared with 
the functionally comparable gill of the lamellibranch mollusca. 

It is difficult, and perhaps impossible, to effect a quantitative consideration of the 
factors considered above, but they are considered to be in some measure responsible 
for the " relict group " nature of existing dasyclads, and for their general subordinate 
position amongst modern marine algal floras. 



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106 CALCAREOUS ALGAE OF THE MIDDLE EAST 

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CALCAREOUS ALGAE OF THE MIDDLE EAST 107 

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Lucknow, 4 : 101-11, 2 pis. 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



109 



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IX. APPENDIX 

Geographical co-ordinates of localities mentioned in the text. 



ABIAD, J. 


56°35'E 


23°35'N 


HAGAB, J. 


56°io'E 


25°45'N 


ADANA 


35 °i8'E 


3 6° 5 8'N 


HAJAR, W. 


48°oo'E 


i4°3o'N 


AIDAH 


43° 4 o'E 


30°5o'N 


HARUR 


43°i5'E 


37°i 4 'N 






approx. 


HAUSHI 


57°4°' E 


2i°oo'N 


AL GHURRA 


43°4o'E 


30°50'N 


HUGF 


57° E 


20 N 






approx. 


JOL BA HAWAR 


48°i8'E 


i4°25'N 


AL HAMIAH 


47° 4 o'E 


i4°oo'N 


JUWEIZA 


55°42'E 


25°i4'N 


ALA-DAG 


2g°3o'E 


36°3o'N 


KASHTI 


45°45'E 


35° 8'N 


AMADIA 


43°29'E 


37 °05'N 


KAUR, J. 


58° E 


22°30'N 


AQABAR KHEMER 


48°i2'E 


i4°48'N 


KIRKUK 


44°24'E 


35°28'N 


AQRA 


43°45'E 


3 6°47'N 


KOI SANJAK 


44°38'E 


36° 5 'N 


ARGOSH 


44°io'E 


37 °8' N 


LAUT, J. 


47°oo'E 


i 4 °i 5 'N 


ARUS, W. 


48°2o'E 


I4°I5'N 


MA'ADI PASS 


49°25'E 


i5°oo'N 


ATSHAN 


42°55'E 


36°2o'N 


MAKHUL 


43°2o'E 


35°i3'N 


AWASIL 


42°49'E 


33°27'N 


MILEH THARTHAR 


4 2°44'E 


32°n'N 


BALAMBO 


45°58'E 


35°7' N 


MINTAQ 


48°oo'E 


i4°3o'N 


BANIK 


4 2° 5 8'E 


37°i2'N 


MURBAN 


53°44'E 


23°53'N 


BASRAH 


47 V 'E 


3o°3o'N 


MUSAIYIB 


44 °25'E 


32°49'N 


BATINAH 


56°57'E 


24°25'N 


ORA 


43°2i'E 


37°i 7 'N 


BEKHME 


44°i4'E 


36°4o'N 


PILA SPI 


45°45'E 


35°i5'N 


BIH, W. 


56°io'E 


25°45'N 


QAMAR, J. 


5 6°o 4 'E 


25°28'N 


BURUN (BURUM) 


49°oo'E 


i4°3o'N 


RAS SADR 


54°44'E 


24 4 8'N 


BUSYAH, J. 


56°io'E 


25°45'N 


ROWANDUZ 


44°33'E 


3 6°37'N 


BUWAIDA, J. 


56°2o'E 


23°io'N 


RU KUCHUK 


44 8'E 


3 6° 5 6'N 


CHALKI 


43°io'E 


37°i4'N 


SAHIL MALEH 


58°4o'E 


23°4o'N 


CHALKI ISLAM (see 


Chalki) 




SARMORD 


45°o2'E 


35°54'N 


CHAMA 


44 i 4 'E 


3 6° 5 o'N 


SEDELAN 


45°oo'E 


35°45'N 


DAMMAM 


5o°oo'E 


26°20'N 


SEKHANIYAN 


45°o9'E 


35°52'N 


DIYANA (DIANA) 


44°33'E 


36°4o'N 


SIRWAN 


46°io'E 


35°Q5'N 


DIZA 


44°i8'E 


3 6° 4 6'N 


SULEMANIA 


45 °26'E 


35°33'N 


DUKHAN 


50°47' E 


25°26'N 


SUNDUR 


43° 4'E 


30°56'N 


FAHUD 


5 6° 3 i'E 


22°l8'N 


SURDASH 


45 °o6'E 


35°5i'N 


FAIYAH, J. 


55°5o'E 


25°io'N 


TAN AMIR, J. 


58°o6'E 


22°39'N 


FALLUJAH 


43°40'E 


33°2i'N 


TAWI SILAIM 


58°35'E 


22°25'N 


GAL-I-MAZURKA 


4 3°29'E 


37°o 5 'N 


WAGSA 


43°45'E 


30°35'N 


GARA, J. 


43°27'E 


36°59'N 


ZIBAR-ISUMERAN 


44° 5'E 


36° 5 2'N 


GHABAR 


4 8°45'E 


i 4 °i3'N 









CALCAREOUS ALGAE OF THE MIDDLE EAST 



si/ fc 




Discs not 
evolved 



Fig. 16. Reproductive Evolution in Dasycladaceae. i. Idealized endospore dasyclad 
(typically Palaeozoic), showing sporangia within the stem-cell and simple, sterile 
branches. No calcification shown : this feature is variable between different known 
genera. 2. Idealized cladospore dasyclad (typically Mesozoic), showing sporangia 
within swollen branches, and separate whorls of fertile and sterile branches. No 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



EXPLANATION OF PLATES 



Unless otherwise stated, all material is housed in the British Museum (Natural 
History). 



calcification shown : this feature is variable between different known genera. 3. 
Clypeina : separate fossil disc and reconstruction of living plant (Permian to Oligocene). 
Separate whorls of naked sterile branches and fertile whorls of fused, heavily-calcified 
branches. Shape and fusion of discs or cups variable between species. 4. Segment of 
Cymopolia eochoristosporica Elliott (Upper Cretaceous), and separate branch-diagram. 
This species transitional between cladospore and choristospore, showing as a small 
cymopoliform branch-system developing on the end of a swollen cladospore branch. 
5. Segment of Cymopolia sp. (Tertiary) and separate branch-diagram, to show typical 
choristospore branch with separate sporangial body at junction of primary and secondary 
branches. Cymopolia is segmented and heavily calcified, but other choristospore genera 
exist which are single (non-segmented) and more lightly calcified. 6. Sketch of portion 
of Halicoryne (Recent) to illustrate choristosporic organization with different proportions 
and arrangement of the component elements. The large elongate gametangium (left) 
is paired with a much smaller sterile branch-system, the whole whorl grouped in a loose 
basket-like circular arrangement. Light incomplete calcification only. 7. Acetabularia 
(Recent). Plant showing typical mature calcified reproductive disc and stem, also 
diagrammatic cross-section of disc. This may be regarded as a fused calcified structure 
analogous to that of Halicoryne (note small sterile branches) : the scars of early sterile 
whorls may be seen on the stem. Acetabularia is thus the choristosporic disc-analogue 
to the cladosporic Clypeina, as now interpreted. 



PLATE i 
Acicularia, Acroporella, Actinoporella, Anthracoporella 

Figs, i, 3. Acicularia antiqua Pia, random cuts in thin-section, x6o. Cretaceous, 
Barremian-Aptian, Upper Musandam Formation : Jebel Hagab, Oman, Arabia. V. 52031. 

Fig. 2. Actinoporella podolica Alth, near-vertical section through stem-cell and two branches 
of one verticil, X28. Cretaceous, Valanginian, Garagu Formation : Banik, Mosul Liwa, 
Iraq. V. 41630. 

Fig. 4. A . podolica, near-horizontal section through a verticil, X45. Cretaceous, Valanginian- 
Hauterivian, Sarmord Formation ; Jebel Gara, Mosul Liwa, Iraq. V. 41579. 

Fig. 5. Acroporella assurbanipali gen. et sp. nov., oblique-vertical section, X20. Holotype. 
Cretaceous, Valanginian-Hauterivian, Garagu Formation ; subsurface, Kirkuk Well no. 116. 
V. 52032. 

Fig. 6. Acicularia (Briardina) sp., thin-section along spicule, x6o. Palaeocene-Lower 
Eocene ; Sahil Maleh, Batinah Coast, Oman, Arabia. V. 52033. 

Fig. 7. A. podolica, typical random tangential-vertical cut through adjacent radial tubules 
of verticil, X30. Cretaceous, Valanginian-Hauterivian, Sarmord Formation ; Jebel Gara, 
Mosul Liwa, Iraq. V. 52034. 

Fig. 8. Anthracoporella mercurii sp. nov., thin-section, holotype. Permian, Bih Dolomite ; 
Wady Bih, Jebel Hagab, Peninsular Oman, Arabia. V. 52035. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 1 









PLATE 2 
Anthracoporella, Atractyliopsis 

Figs, i, 2. Anthracoporella spectabilis Pia, thin-section x 12, and portion enlarged to show 
wall-detail, x 24. Permian ; derived cobble in Triassic conglomerate ; Jebel Busyah, Oman, 
Arabia. V. 52036. 

Figs. 3-5. Atractyliopsis darariensis sp. nov. Thin-sections ; 3. Paratype, oblique- 
vertical, X28 V. 52015 ; 4. Paratype, vertical, incomplete example, X40 V. 52037 ; 5. Holo- 
type, vertical, long gently-curved example, x 20 V. 52037. Upper Permian, Darari Formation; 
Ora, Mosul Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 2 







PLATE 3 
Broeckella, Clypeina 

Fig. i. Broeckella belgica Morellet, transverse thin-section, X50. Palaeocene ; Sahil 
Maleh, Batinah Coast, Oman, Arabia. 

Figs. 2, 3. Clypeina jurassica Favre, thin-sections, X30. 2. Associated fragments ; above, 
transverse (horizontal) section of broken verticil, showing radial tubules with example of 
communicatory pore to stem-cell on right and distinctive thin-section appearance of adjacent 
tubules in this species at top centre ; below, tangential-vertical cut of thick-walled tubules at 
about mid-tubule zone radially. V. 52038. 3. Oblique-vertical cut of plant with successive 
verticils in position ; the plane of section passes from central (below) to obliquely through 
stem-cell wall and inner tubule-junction (middle) to outer tubules of third verticil. V. 52039. 
Upper Jurassic, Najmah Formation ; subsurface, Kirkuk Well No. 117, Iraq. 

Fig. 4. C. jurassica, slightly oblique transverse cut through one verticil, x 30. Upper 
Jurassic, Arab Zone ; subsurface, Dukhan No. 28 Well, Qatar, Arabia. V. 52040. 

Fig. 5. C. jurassica, transverse cut through one worn verticil, showing the resistant nature 
of the calcification at the fusion between adjacent tubules, X30. Upper Jurassic, Najmah 
Formation ; subsurface, Kirkuk Well No. 117, Iraq. V. 52041. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 3 









to 


Are 

■f 




1 * 


t«l K 






T . i , ,-T ^..:- ..A: ~- 



PLATE 4 
Clypeina 

Fig. i. Clypeina marteli Emberger, transverse thin-section, X28. Cretaceous, Valanginian ; 
Hugf, Southern Oman, Arabia. V. 52042. 

Fig. 2. Clypeina merienda Elliott, oblique-transverse thin-section through verticil to show 
bases of tubules and part of central ring. X35. Palaeocene, Sinjar Formation ; Koi Sanjak, 
Erbil Liwa, Iraq. V. 52043. 

Figs. 3, 7, 8. C. merienda, thin sections, X28. Palaeocene, Sinjar Limestone. 3. Trans- 
verse cut of broken verticil. Sirwan, Sulemania Liwa, Iraq. V. 41586. 7. Oblique cut of 
successive verticils. Koi Sanjak, Erbil Liwa, Iraq. V. 52043. 8. Vertical-tangential cut of 
numerous successive verticils of one plant. Sirwan, Sulemania Liwa, Iraq. V. 41587. 

Figs. 4, 5, 6. C. jurassica, solid (dissociated) verticils, showing top, side and bottom appear- 
ances, X28. Upper Jurassic, Arab zone ; subsurface, Dukhan No. 2 Well, Qatar, Arabia. 
V. 52044, V. 52045, V. 52046. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 4 














J 

1 ... • » . 


ftp 


IF ■ ^^ 


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I * . ■ 


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1 . ft* 






PLATE 5 
Clypeina 

Figs, i, 3. Clypeina (" Eoclypeina") sp., thin-sections of debris, X40. Permian, basal 
Satina Formation and top Zinnar Formation respectively ; Harur, Mosul Liwa, Iraq. V. 41598, 
V. 52048. 

Fig. 2. Clypeina sp., slightly oblique-transverse section of verticil, X30. Palaeocene ; 
Ghurra Beds, Umm er Radhama Formation ; Al Ghurra, Diwaniya Liwa, Iraq. V. 52047. 

Fig. 4. Clypeina lucasi Emberger, oblique-transverse section of verticil, X28. Cretaceous. 
Valanginian ; Hugf area, Southern Oman, Arabia. V. 52042. 

Figs. 5, 6. Clypeina parvula Carozzi, thin-sections showing random transverse and frag- 
mentary longitudinal sections, x6o. Cretaceous, Valanginian, Garagu Formation ; subsurface, 
Kirkuk Well No. 116, Iraq. V. 52049, V. 52050. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 5 







PLATE 6 
Cylindroporella 

Figs, i, 2. Cylindroporella arabica Elliott, longitudinal and transverse thin-sections, X58. 
Upper Jurassic, " Arab Zone " ; subsurface, Dukhan No. 28 Well, Qatar, Arabia. V. 41629. 

Figs. 3,4. Cylindroporella barnesi Johnson. 3. Random oblique section, X30. Cretaceous, 
Valanginian-Hauterivian, Garagu Formation ; subsurface, Makhul No. 2 Well, Mosul Liwa, 
Iraq. V. 52051. 4. Random tangential section, x6o. Cretaceous, about Aptian level, 
Sarmord Formation ; Sekhaniyan, Surdash, Sulemania Liwa, Iraq. V. 52052. 

Figs. 5-7. Cylindroporella sugdeni Elliott. 5. Longitudinal section, X35. V. 52053. 
6. Transverse section, X28. V. 41623. 7. Tangential section, X28. V. 41620. Lower 
Cretaceous ; subsurface, Fahud No. 1 Well, Oman, Arabia. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 6 



££ I 










PLATE 



Cymopolia 



Figs. 1-5. Cymopolia anadyomenea 
2. Transverse section, X28. V. 41656 
5. Solid specimen on weathered surface, X20. V. 52054. 



Formation ; Diza North, Erbil Liwa, Iraq 



Elliott. 1. Longitudinal section, X28. V. 41656. 

3, 4. Oblique sections, X28. V. 41656, V. 41655. 

Cretaceous, Maestrichtian, Tanjero 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 7 




PLATE 8 
Cymopolia 

Figs, i, 5. Cymopolia anadyomenea Elliott, i. Oblique-transverse section, X28. Creta- 
ceous, Maestrichtian, Tanjero Formaton ; Diza North, Erbil Liwa, Iraq. V. 52055. 5. Debris, 
in limestone facies, thin-section x 20. Cretaceous, Maestrichtian, Upper Aqra Formation ; 
Aqra, Mosul Liwa, Iraq. V. 52056. 

Fig. 2. Cymopolia barberae sp. nov., holotype, transverse thin-section, X50. Palaeocene- 
Lower Eocene, Kolosh Formation ; Surdash, Sulamenia Liwa, Iraq. V. 52057. 

Figs. 3, 4. Cymopolia tibetica Morellet. 3. Transverse section, x6o. Cretaceous, Mae- 
strichtian, Aqra Formation ; Aqra, Mosul Liwa, Iraq. V. 52059. 4. Fragment to show 
branch-structure, thin-section, x6o. Cretaceous, Maestrichtian, Aqra-Hadiena Limestone 
Facies ; Chalki Islam, Mosul Liwa, Iraq. V. 52060. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 8 




PLATE 9 

Cymopolia 

Figs. 1-3. Cymopolia eochoristosporica sp. nov. 1. Oblique-longitudinal thin-section, X20. 
Holotype, V. 52652. 2. The same, to show branch and sporangial-detail, X40. 3. Another 
oblique-longitudinal thin-section, portion X40. Syntype, V. 52653. Both from Cretaceous, 
Maestrichtian, subsurface Aruma Formation ; Murban No. 53 Well, Abu Dhabi, Trucial Oman, 
Arabia. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 9 






PLATE 10 
Cymopolia, Dissocladella 

Fig. i. Cymopolia elongata (Defrance) Mun.-Chalmas. Solid specimen, small single unit or 
segment, X 28, for comparison of external pores (branch-openings) with those of C. kurdistanensis 
(fig. 2). Eocene, Lutetian ; Grignon, Paris, France. V. 52061. 

Figs. 2-5. Cymopolia kurdistanensis Elliott. 2. Solid specimen, single segment, to show 
detail of exterior, X28. Palaeocene-Lower Eocene, Kolosh Formation, Bekhme, Erbil Liwa, 
Iraq. V. 52062. 3. Thin-section of dissociated segment, to show details of sporangia and 
branches, X28. Palaeocene, Sinjar Formation ; Banik, Mosul Liwa, Iraq. V. 41593. 
4. Slightly oblique transverse cut showing sporangia and branches, X 36. Palaeocene, Kolosh 
Formation ; Rowanduz, Erbil Liwa, Iraq. V. 52063. 5. Random transverse section at an 
inter-sporangial level so that only the branches are seen, x 30. Palaeocene ; Jebel Faiyah, 
Trucial Oman, Arabia. V. 52064. 

Fig. 6. Cymopolia (Karreyia) sp. Thin-section fragment to show sporangia, etc., X50. 
Palaeocene-Lower Eocene, Sinjar Formation ; Pila Spi, Sulemania Liwa, Iraq. V. 52065. 

Figs. 7, 8. Dissocladella deserta sp. nov. Syntypes. 7. Longitudinal section, X50. 
V. 52066. 8. Transverse section, X50. V. 52067. Palaeocene-Lower Eocene, Umm er 
Rudhama Formation ; Aidah and Wagsa, Diwaniyah Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 10 






y 






i0i 






M, 




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iVvJ 










PLATE ii 
Dissocladella, Furcoporella 

Figs. 1-3. Dissocladella savitriae Pia. 1. Transverse section, X28. Palaeocene, Sinjar 
Formation ; Banik, Mosul Liwa, Iraq. V. 41580. 2. Fragment to show enlarged wall-struc- 
ture, thin-section, X50. Palaeocene, Kolosh Formation ; Rowanduz, Erbil Liwa, Iraq. 
V. 52068. 3. Broken solid specimen to show nodose-annular external appearance, x 28. Lower 
Eocene ; subsurface, Dukhan No. 3 Well ; Qatar, Arabia. V. 52069. 

Figs. 4—6. Dissocladella undulata (Raineri) Pia. Thin-sections. 4. Transverse section, 
X50. V. 52070. 5, 6. Near-longitudinal sections, X50. V. 52071. Cretaceous, Turonian, 
Sadi Formation, subsurface, Musaiyib No. 1 Well, Hill Liwa, Iraq. 

Figs. 7-9. Furcoporella diplopora Pia. 7. Oblique-longitudinal section to show successively 
divergent pore-pairs (lower part of figure), X38. V. 41606. 8. Longitudinal section to show 
waisted pores, X30. V. 41606. 9. Transverse section to show paired branches, X45. V. 
51232. Palaeocene-Lower Eocene, Kolosh Formation ; Sedelan, Sulemania Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 11 












PLATE 12 
Griphoporella, Indopolia 

Figs. 1,3. " Griphoporella arabica Pfender " (Ovulites maillolensis Massieux). Transverse 
and oblique longitudinal sections, X50. Palaeocene-Lower Eocene ; Sahil Maleh, Batinah 
Coast, Oman, Arabia. V. 52033. 

Fig. 2. Indopolia satyavanti Pia. Oblique-longitudinal section showing sterile whorls, X50. 
Palaeocene-Lower Eocene, Sinjar Formation ; Banik, Mosul Liwa, Iraq. V. 52072. 

Fig. 4. Griphoporella cf. perforatissima Carozzi. Tangential section of wall-fragment, X 50. 
Upper Jurassic, Najmah Formation ; subsurface, Kirkuk Well No. 117, Iraq. V. 52073. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 12 






PLATE 13 

Mizzia 

Figs. 1-5. Mizzia velebitana Schubert, thin-sections of separate bead-like units or segments, 
X28. 1. Slightly oblique longitudinal section. V. 52074. 2, 3. Typical transverse sections 
near equatorial region. V. 52075, V. 41575. 4. Random sections, the lower suggests externally 
roofed branch-pores. 5. Three random sections : the upper is of a pear-shaped segment cut 
longitudinally. V. 52076. Permian, Darari Formation ; fig. 3 from Harur, the others from 
Ora, both localities in Mosul Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 13 




PLATE 14 

Mizzia 

Figs. 1-4. Mizzia velebitana Schubert, thin-sections. 1. Transverse cut of unit with roofed 
pores, X28. 2. Longitudinal-oblique section of unit, X28. 3. Tangential cut to show 
typical coarse "colander-pore" pattern; also longitudinal section of broken unit, X28. 
4. Random section of Mizzia-xock, X20. Permian, Darari Formation ; Ora, Mosul Liwa, 
Iraq. V. 52076. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 14 




PLATE 15 
Neomeris, Munieria 

Fig. 1. Neomeris cretacea Steinmann. Oblique-longitudinal section, X20. Cretaceous, 
Maestrichtian, Bekhme Formation ; Chia Gara, Mosul Liwa, Iraq. V. 52077. 

Fig. 2. N. cretacea. Oblique-transverse section, X28. Cretaceous, Campanian-Maestrich- 
tian, Aqra-Bekhme limestone facies ; Gal-i-Mazurka, Mosul Liwa, Iraq. V. 41585. 

Figs. 3-8. Munieria baconica Deecke. Typical fragmentary remains, thin-sections, X50. 
3, 4, 6. Cretaceous, Aptian level, Qamchuqa Formation ; Ru Kuchuk, Mosul Liwa, Iraq. 
V. 52078. 5, 7. Cretaceous, Barremian level, Sarmord Formation ; Sarmord, Sulemiania Liwa, 
Iraq. V. 52079. 8. Cretaceous, Aptian-Albian level, Qamchuqa Formation ; Surdash, 
Sulemania Liwa, Iraq. V. 52080. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 15 



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PLATE 16 

Palaeodasycladus 

Figs. 1-5. Palaeodasycladus mediterraneus Pia. 1, 2. Longitudinal, and two transverse 
sections, X20. V. 52081. 3. Fragment to show detail of branch-constrictions, X28. V. 52082. 
4. Oblique-transverse cut to show effect of angle of branch-inclination. V. 52082. 5. Detail of 
terminal branches, X20. V. 52083. Jurassic, Lias, Lower Musandam Formation ; Wady 
Bih, Qamar, Peninsular Oman, Arabia. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 16 




PLATE 17 
Permoperplexella, Pianella, Pagodaporella 

Figs. 1-5. Permoperplexella attenuata gen. et sp. nov., thin-sections, X28. 1. Paratype, 
oblique-longitudinal cut. V. 52084. 2, 3. Paratypes, oblique section of distal end, oblique- 
transverse cut near this end. V. 52085. 4. Holotype, longitudinal section. V. 52085. 
5. Oblique-transverse cut near distal end. V. 52085. Permian, Zinnar Formation ; Ora, 
Mosul Liwa, Iraq. 

Figs. 6-8. Pianella pygmaea (Giimbel) Radoicic. 6. Transverse section, X40. V. 52086. 
7. Longitudinal section, X40. V. 52087. 8. Oblique section, X40. V. 52088. Cretaceous, 
Valanginian, Garagu Formation ; subsurface, Mileh Tharthar Well No. 1, Dulaim Liwa, Iraq. 

Figs. 9, 10. Pagodaporella wetzeli Elliott. 9. Longitudinal thin-section of solid, dissociated, 
example, x6o. V. 41605. 10. Solid example, external appearance, x6o. V. 41604. Palae- 
ocene, Kolosh Formation ; Bekhme, Erbil Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 




PLATE 18 
Pseudoepimastopora 

Figs, i, 2. Pseudoepimastopora ampullacea sp. nov. 1. Holotype, longitudinal section of 
" waxing-and-waning " example, X30. V. 52089. 2. Paratype, random section of long 
curved piece of thallus, X30. V. 52090. Permian, Zinnar Formation ; Ora, Mosul Liwa, 
Iraq. 

Figs. 3, 4. Pseudoepimastopora cf. likana Kochansky and Herak. Fragments of wall- 
material showing large distinctive pores, thin-sections, X30. Permian ; Jebel Qamar, 
Peninsular Oman, Arabia. V. 52091, 52092. 

Figs. 5-7. P. ampullacea. 5, 6. Thin-sections of wall-fragments showing clearly the form 
of the pores, x6o. V. 52093. 7. Transverse section, x6o. V. 52094. Permian, Zinnar 
Formation ; Ora, Mosul Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 18 




PLATE 19 

Pseudovermiporella 

Figs. 1-5. Pseudovermiporella sodalica Elliott. Thin-sections, X50. 1, 2. Portions of 
large individuals showing typical coarse mesh of main tube, supposed diagenetic lining layers, 
inner tube and irregular meandriform growth ; in fig. 2 mesh of a second small individual is 
seen in position of growth on the inner tube of the main individual. V. 41641, V. 41645, 
3. Transverse cut of typical single unattached tube. V. 41644. 4, 5. Sections of small early 
clusters or " nucleo-conch " structures ; in fig. 4 the reniform, calcite-filled structure is 
unusually large but is apparently an early inner tube. 41649, 41642. Permian; Jebel Qamar, 
Peninsular Oman, Arabia. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl 



PLATE 19 







PLATE 20 
Salpingoporella 

Figs, i, 2, 5. Salpingoporella apenninica Sartoni & Crescenti. Thin-sections, X50. 1. 
Random vertical and transverse cuts of short lengths of tube. V. 52095. 2, 5. Longitudinal 
sections with associated transverse sections. V. 52096. Upper Jurassic, Najmah Formation ; 
subsurface, Kirkuk Well No. 117, Iraq. 

Figs. 3, 4, 6, 7. Salpingoporella annulata Carozzi. 3. Oblique-vertical section, X50. 
V. 52097. 4. Transverse section, X50. V. 52099. 6. Solid (dissociated) specimen, 
external appearance, X50. V. 52099. 7. Longitudinal thin-section, X50. V. 52098. Upper 
Jurassic, " Arab Zone " ; subsurface, Dukhan Well No. 28 (figs. 3, 4, 7) and Well No. 2 (fig. 6), 
Qatar, Arabia. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 


PLATE 20 


WbB^3Bc^*HStiE 




■■ ^^.^rBur Bl B ' Mfs^k^k bC-^B B7J> ^b 
BLyy V**LdH Br' ■ ■ K 1 orasnu 











PLATE 21 
Salpingoporella 

Fig. i. Salpingoporella arabica sp. nov. Paratype, oblique-longitudinal thin-section, wall 
replaced by clear calcite, x 50. Cretaceous, Albian-Cenomanian level, top Qamchuqa Forma- 
tion ; Sarmord, Sulemania Liwa, Iraq. V. 52100. 

Fig. 2. S. arabica. Paratypes, oblique-transverse sections to show simple branch-structure, 
X 50. Lower Cretaceous, Upper Musandam Formation ; Jebel Hagab, Peninsular Oman, 
Arabia. V. 52101. 

Fig. 3. S. arabica. Holotype, longitudinal section, X40. Cretaceous, Aptian-Albian level, 
Qamchuqa Formation ; Surdash, Sulemania Liwa, Iraq. V. 52102. 

Fig. 4. Salpingoporella dinarica Radoicic (Hensonella cylindrica Elliott). Numerous typical 
random cuts in thin-section, x 50. Cretaceous, Barremian-Aptian level, Sarmord Formation ; 
Sekhaniyan, Surdash, Sulemania Liwa, Iraq. (Compare preservation with that of S. arabica 
above). V. 52103. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 21 




PLATE 22 
Salpingoporella dinarica (Hensonella) 

Fig. i. Part of the type thin-section, X30, of Hensonella cylindrica Elliott. Cretaceous, 
Barremian, Qamchuqa Formation ; Sarmord, Sulemania Liwa, Iraq. Z. 902. 

Fig. 2. S. dinarica Radoicic. Thin-section X50, oblique-longitudinal cut, to show dasyclad 
branch-pore pattern as described by Radoicic. Cretaceous, Upper Aptian ; Djebel Amsid, 
Constantinois, Algeria. V. 52104. 

Figs. 3-6. Thin-section cuts, X50. 3. Crushed example to show continuity of inner thin 
dark layer. V. 52103. 4. Random sections, one crushed. V. 52103. 5. Longitudinal and 
transverse sections showing very regular fibrous radial structure and coarser features with 
external widening interpreted as dasyclad branches. V. 52103. 6. Transverse section showing 
the inner dark layer of organism incrusted by a thin irregular coating of transparent calcite, the 
interior being filled with darker marly-calcareous matrix. V. 52105. Cretaceous, Barremian- 
Aptian level, Sarmord Formation ; Sekhaniyan, Surdash, Sulemania Liwa, Iraq. 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 22 




PLATE 23 
Terquemella, Thyr sopor ella 

Figs, i, 2. Thyrsoporella silvestrii Pfender. 1. Transverse section, X50. V. 52106. 
2. Longitudinal section, X50. V. 52107. Middle Eocene ; Jebel Tanamir, Fatah, 
Oman, Arabia. 

Fig. 3. T. silvestrii. Tangential-longitudinal section, X50. Palaeocene-Lower Eocene, 
Kolosh Formation ; Sedelan, Sulemania Liwa, Iraq. V. 52108. 

Fig. 4. T. silvestrii. Longitudinal section of large individual, X28. Middle Eocene ; 
Jebel Tanamir, Fatah, Oman, Arabia. V. 52109. 

Fig. 5. Terquemella globularis Elliott. Solid specimen to show exterior, x8o. Palaeocene, 
Kolosh Formation ; Bekhme, Erbil Liwa, Iraq. V. 41603. 

Figs. 6, 7. Terquemella bellovacensis Munier-Chalmas. 6. Tangential-transverse section, 
X55- V. 41589. 7. Vertical section, X55. V. 41590. Palaeocene-Lower Eocene, Sinjar 
Formation ; Sirwan, Sulemania Liwa, Iraq. 

Fig. 8. T. globularis. Thin-sections, X55. Palaeocene-Lower Eocene, Sinjar Formation ; 
Sirwan, Sulemania Liwa, Iraq. V. 32496. 



vr 



Bull. Br. Mus. nat. Hist. (Geol.) Suppl. 4 



PLATE 23 







PLATE 24 
Thyrsoporella, Trinocladus 

Figs, i, 2, 6, 7. Trinocladus perplexus Elliott. 1. Solid specimen to show exterior, X50. 
V. 521 17. 2. Longitudinal section of specimen in which an example of the codiacid Ovulites 
morelleti Elliott perfectly fits the stem-cell cavity of the larger fossil, X50. V. 521 10. 
6. Oblique and transverse sections, X50. V. 521 14. 7. Near-longitudinal section to show 
branch-structure, X50. V. 521 15. Palaeocene-Lower Eocene, Kolosh Formation ; Koi 
Sanjak, Erbil Liwa, Iraq. 

Fig. 3. Trinocladus tripolitanus Raineri. Longitudinal section, X50. Cretaceous, Turonian ; 
subsurface, Ras Sadr Well No. 1, Trucial Oman, Arabia. V. 521 11. 

Fig. 4. T. tripolitanus. Oblique-transverse section, X50. Cretaceous, Turonian, Sadr 
Formation ; Musaiyib Well No. 1, Hilla Liwa, Iraq. V. 521 12. 

Fig. 5. Thyrsoporella silvestrii Pfender. Thin-section fragment to show detail of branch- 
structure, X50. Middle Eocene ; Jebel Tanamir, Fatah, Oman, Arabia. V. 52113. 

Fig. 8. Trinocladus radoicicae sp. nov. Syntypes, transverse sections, X50. Cretaceous, 
Maestrichtian, Tanjero Formation ; Diza, Erbil Liwa, Iraq. V. 52 116. 







Bull. Br. Mus. nal. Hist. (Geol.) Suppl. 4 





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